diff --git a/packages/istanbul-lib-source-maps/lib/transformer.js b/packages/istanbul-lib-source-maps/lib/transformer.js
index 3d26c515..6f635383 100644
--- a/packages/istanbul-lib-source-maps/lib/transformer.js
+++ b/packages/istanbul-lib-source-maps/lib/transformer.js
@@ -14,6 +14,7 @@ class SourceMapTransformer {
     constructor(finder, opts = {}) {
         this.finder = finder;
         this.baseDir = opts.baseDir || process.cwd();
+        this.resolveMapping = opts.getMapping || getMapping;
     }
 
     processFile(fc, sourceMap, coverageMapper) {
@@ -21,7 +22,7 @@ class SourceMapTransformer {
 
         Object.entries(fc.statementMap).forEach(([s, loc]) => {
             const hits = fc.s[s];
-            const mapping = getMapping(sourceMap, loc, fc.path);
+            const mapping = this.resolveMapping(sourceMap, loc, fc.path);
 
             if (mapping) {
                 changes += 1;
@@ -32,8 +33,17 @@ class SourceMapTransformer {
 
         Object.entries(fc.fnMap).forEach(([f, fnMeta]) => {
             const hits = fc.f[f];
-            const mapping = getMapping(sourceMap, fnMeta.decl, fc.path);
-            const spanMapping = getMapping(sourceMap, fnMeta.loc, fc.path);
+            const mapping = this.resolveMapping(
+                sourceMap,
+                fnMeta.decl,
+                fc.path
+            );
+
+            const spanMapping = this.resolveMapping(
+                sourceMap,
+                fnMeta.loc,
+                fc.path
+            );
 
             if (
                 mapping &&
@@ -59,7 +69,7 @@ class SourceMapTransformer {
             let skip;
 
             branchMeta.locations.forEach((loc, i) => {
-                const mapping = getMapping(sourceMap, loc, fc.path);
+                const mapping = this.resolveMapping(sourceMap, loc, fc.path);
                 if (mapping) {
                     if (!source) {
                         source = mapping.source;
@@ -74,12 +84,16 @@ class SourceMapTransformer {
                 }
             });
 
+            const locMapping = branchMeta.loc
+                ? this.resolveMapping(sourceMap, branchMeta.loc, fc.path)
+                : null;
+
             if (!skip && locs.length > 0) {
                 changes += 1;
                 const mappedCoverage = coverageMapper(source);
                 mappedCoverage.addBranch(
                     branchMeta.type,
-                    locs[0] /* XXX */,
+                    locMapping ? locMapping.loc : locs[0],
                     locs,
                     mappedHits
                 );
diff --git a/packages/istanbul-lib-source-maps/test/testdata/switchBranchCoverageData.json b/packages/istanbul-lib-source-maps/test/testdata/switchBranchCoverageData.json
new file mode 100644
index 00000000..671b3f41
--- /dev/null
+++ b/packages/istanbul-lib-source-maps/test/testdata/switchBranchCoverageData.json
@@ -0,0 +1,408 @@
+{
+    "path": "dummyFile.js",
+    "statementMap": {
+        "0": {
+            "start": {
+                "line": 2,
+                "column": 0
+            },
+            "end": {
+                "line": 2,
+                "column": 62
+            }
+        },
+        "1": {
+            "start": {
+                "line": 3,
+                "column": 29
+            },
+            "end": {
+                "line": 3,
+                "column": 60
+            }
+        },
+        "2": {
+            "start": {
+                "line": 4,
+                "column": 29
+            },
+            "end": {
+                "line": 4,
+                "column": 60
+            }
+        },
+        "3": {
+            "start": {
+                "line": 5,
+                "column": 30
+            },
+            "end": {
+                "line": 5,
+                "column": 62
+            }
+        },
+        "4": {
+            "start": {
+                "line": 8,
+                "column": 8
+            },
+            "end": {
+                "line": 8,
+                "column": 45
+            }
+        },
+        "5": {
+            "start": {
+                "line": 9,
+                "column": 8
+            },
+            "end": {
+                "line": 9,
+                "column": 29
+            }
+        },
+        "6": {
+            "start": {
+                "line": 12,
+                "column": 8
+            },
+            "end": {
+                "line": 12,
+                "column": 107
+            }
+        },
+        "7": {
+            "start": {
+                "line": 15,
+                "column": 8
+            },
+            "end": {
+                "line": 18,
+                "column": 9
+            }
+        },
+        "8": {
+            "start": {
+                "line": 17,
+                "column": 12
+            },
+            "end": {
+                "line": 17,
+                "column": 24
+            }
+        },
+        "9": {
+            "start": {
+                "line": 19,
+                "column": 8
+            },
+            "end": {
+                "line": 23,
+                "column": 9
+            }
+        },
+        "10": {
+            "start": {
+                "line": 22,
+                "column": 12
+            },
+            "end": {
+                "line": 22,
+                "column": 111
+            }
+        },
+        "11": {
+            "start": {
+                "line": 24,
+                "column": 8
+            },
+            "end": {
+                "line": 32,
+                "column": 9
+            }
+        },
+        "12": {
+            "start": {
+                "line": 27,
+                "column": 16
+            },
+            "end": {
+                "line": 27,
+                "column": 115
+            }
+        },
+        "13": {
+            "start": {
+                "line": 29,
+                "column": 16
+            },
+            "end": {
+                "line": 29,
+                "column": 116
+            }
+        },
+        "14": {
+            "start": {
+                "line": 31,
+                "column": 16
+            },
+            "end": {
+                "line": 31,
+                "column": 115
+            }
+        },
+        "15": {
+            "start": {
+                "line": 35,
+                "column": 0
+            },
+            "end": {
+                "line": 35,
+                "column": 37
+            }
+        }
+    },
+    "fnMap": {
+        "0": {
+            "name": "(anonymous_0)",
+            "decl": {
+                "start": {
+                    "line": 7,
+                    "column": 4
+                },
+                "end": {
+                    "line": 7,
+                    "column": 5
+                }
+            },
+            "loc": {
+                "start": {
+                    "line": 7,
+                    "column": 40
+                },
+                "end": {
+                    "line": 10,
+                    "column": 5
+                }
+            },
+            "line": 7
+        },
+        "1": {
+            "name": "(anonymous_1)",
+            "decl": {
+                "start": {
+                    "line": 11,
+                    "column": 4
+                },
+                "end": {
+                    "line": 11,
+                    "column": 5
+                }
+            },
+            "loc": {
+                "start": {
+                    "line": 11,
+                    "column": 48
+                },
+                "end": {
+                    "line": 13,
+                    "column": 5
+                }
+            },
+            "line": 11
+        },
+        "2": {
+            "name": "(anonymous_2)",
+            "decl": {
+                "start": {
+                    "line": 14,
+                    "column": 4
+                },
+                "end": {
+                    "line": 14,
+                    "column": 5
+                }
+            },
+            "loc": {
+                "start": {
+                    "line": 14,
+                    "column": 41
+                },
+                "end": {
+                    "line": 33,
+                    "column": 5
+                }
+            },
+            "line": 14
+        }
+    },
+    "branchMap": {
+        "0": {
+            "loc": {
+                "start": {
+                    "line": 15,
+                    "column": 8
+                },
+                "end": {
+                    "line": 18,
+                    "column": 9
+                }
+            },
+            "type": "if",
+            "locations": [
+                {
+                    "start": {
+                        "line": 15,
+                        "column": 8
+                    },
+                    "end": {
+                        "line": 18,
+                        "column": 9
+                    }
+                },
+                {
+                    "start": {
+                        "line": 15,
+                        "column": 8
+                    },
+                    "end": {
+                        "line": 18,
+                        "column": 9
+                    }
+                }
+            ],
+            "line": 15
+        },
+        "1": {
+            "loc": {
+                "start": {
+                    "line": 19,
+                    "column": 8
+                },
+                "end": {
+                    "line": 23,
+                    "column": 9
+                }
+            },
+            "type": "if",
+            "locations": [
+                {
+                    "start": {
+                        "line": 19,
+                        "column": 8
+                    },
+                    "end": {
+                        "line": 23,
+                        "column": 9
+                    }
+                },
+                {
+                    "start": {
+                        "line": 19,
+                        "column": 8
+                    },
+                    "end": {
+                        "line": 23,
+                        "column": 9
+                    }
+                }
+            ],
+            "line": 19
+        },
+        "2": {
+            "loc": {
+                "start": {
+                    "line": 24,
+                    "column": 8
+                },
+                "end": {
+                    "line": 32,
+                    "column": 9
+                }
+            },
+            "type": "switch",
+            "locations": [
+                {
+                    "start": {
+                        "line": 25,
+                        "column": 12
+                    },
+                    "end": {
+                        "line": 25,
+                        "column": 27
+                    }
+                },
+                {
+                    "start": {
+                        "line": 26,
+                        "column": 12
+                    },
+                    "end": {
+                        "line": 27,
+                        "column": 115
+                    }
+                },
+                {
+                    "start": {
+                        "line": 28,
+                        "column": 12
+                    },
+                    "end": {
+                        "line": 29,
+                        "column": 116
+                    }
+                },
+                {
+                    "start": {
+                        "line": 30,
+                        "column": 12
+                    },
+                    "end": {
+                        "line": 31,
+                        "column": 115
+                    }
+                }
+            ],
+            "line": 24
+        }
+    },
+    "s": {
+        "0": 1,
+        "1": 1,
+        "2": 1,
+        "3": 1,
+        "4": 3,
+        "5": 3,
+        "6": 0,
+        "7": 0,
+        "8": 0,
+        "9": 0,
+        "10": 0,
+        "11": 0,
+        "12": 0,
+        "13": 0,
+        "14": 0,
+        "15": 1
+    },
+    "f": {
+        "0": 3,
+        "1": 0,
+        "2": 0
+    },
+    "b": {
+        "0": [
+            0,
+            0
+        ],
+        "1": [
+            0,
+            0
+        ],
+        "2": [
+            0,
+            0,
+            0,
+            0
+        ]
+    }
+}
diff --git a/packages/istanbul-lib-source-maps/test/testdata/switchBranchCoverageDataExpectedResult.json b/packages/istanbul-lib-source-maps/test/testdata/switchBranchCoverageDataExpectedResult.json
new file mode 100644
index 00000000..805ddd6d
--- /dev/null
+++ b/packages/istanbul-lib-source-maps/test/testdata/switchBranchCoverageDataExpectedResult.json
@@ -0,0 +1,391 @@
+{
+    "path": "dummyFile.ts",
+    "statementMap": {
+        "0": {
+            "start": {
+                "line": 7,
+                "column": 0
+            },
+            "end": {
+                "line": 7,
+                "column": 54
+            }
+        },
+        "1": {
+            "start": {
+                "line": 8,
+                "column": 0
+            },
+            "end": {
+                "line": 8,
+                "column": 54
+            }
+        },
+        "2": {
+            "start": {
+                "line": 9,
+                "column": 0
+            },
+            "end": {
+                "line": 9,
+                "column": 56
+            }
+        },
+        "3": {
+            "start": {
+                "line": 16,
+                "column": 8
+            },
+            "end": {
+                "line": 16,
+                "column": 45
+            }
+        },
+        "4": {
+            "start": {
+                "line": 17,
+                "column": 8
+            },
+            "end": {
+                "line": 17,
+                "column": 29
+            }
+        },
+        "5": {
+            "start": {
+                "line": 21,
+                "column": 8
+            },
+            "end": {
+                "line": 21,
+                "column": 110
+            }
+        },
+        "6": {
+            "start": {
+                "line": 25,
+                "column": 8
+            },
+            "end": {
+                "line": 28,
+                "column": null
+            }
+        },
+        "7": {
+            "start": {
+                "line": 27,
+                "column": 12
+            },
+            "end": {
+                "line": 27,
+                "column": 24
+            }
+        },
+        "8": {
+            "start": {
+                "line": 29,
+                "column": 8
+            },
+            "end": {
+                "line": 33,
+                "column": null
+            }
+        },
+        "9": {
+            "start": {
+                "line": 32,
+                "column": 12
+            },
+            "end": {
+                "line": 32,
+                "column": 114
+            }
+        },
+        "10": {
+            "start": {
+                "line": 35,
+                "column": 8
+            },
+            "end": {
+                "line": 43,
+                "column": null
+            }
+        },
+        "11": {
+            "start": {
+                "line": 38,
+                "column": 16
+            },
+            "end": {
+                "line": 38,
+                "column": 118
+            }
+        },
+        "12": {
+            "start": {
+                "line": 40,
+                "column": 16
+            },
+            "end": {
+                "line": 40,
+                "column": 119
+            }
+        },
+        "13": {
+            "start": {
+                "line": 42,
+                "column": 16
+            },
+            "end": {
+                "line": 42,
+                "column": 118
+            }
+        },
+        "14": {
+            "start": {
+                "line": 11,
+                "column": 0
+            },
+            "end": {
+                "line": 11,
+                "column": 21
+            }
+        }
+    },
+    "fnMap": {
+        "0": {
+            "name": "(anonymous_0)",
+            "decl": {
+                "start": {
+                    "line": 15,
+                    "column": 4
+                },
+                "end": {
+                    "line": 15,
+                    "column": 16
+                }
+            },
+            "loc": {
+                "start": {
+                    "line": 15,
+                    "column": 64
+                },
+                "end": {
+                    "line": 18,
+                    "column": 5
+                }
+            }
+        },
+        "1": {
+            "name": "(anonymous_1)",
+            "decl": {
+                "start": {
+                    "line": 20,
+                    "column": 11
+                },
+                "end": {
+                    "line": 20,
+                    "column": 29
+                }
+            },
+            "loc": {
+                "start": {
+                    "line": 20,
+                    "column": 80
+                },
+                "end": {
+                    "line": 22,
+                    "column": 5
+                }
+            }
+        },
+        "2": {
+            "name": "(anonymous_2)",
+            "decl": {
+                "start": {
+                    "line": 24,
+                    "column": 11
+                },
+                "end": {
+                    "line": 24,
+                    "column": 22
+                }
+            },
+            "loc": {
+                "start": {
+                    "line": 24,
+                    "column": 73
+                },
+                "end": {
+                    "line": 44,
+                    "column": 5
+                }
+            }
+        }
+    },
+    "branchMap": {
+        "0": {
+            "loc": {
+                "start": {
+                    "line": 25,
+                    "column": 8
+                },
+                "end": {
+                    "line": 28,
+                    "column": null
+                }
+            },
+            "type": "if",
+            "locations": [
+                {
+                    "start": {
+                        "line": 25,
+                        "column": 8
+                    },
+                    "end": {
+                        "line": 28,
+                        "column": null
+                    }
+                },
+                {
+                    "start": {
+                        "line": 25,
+                        "column": 8
+                    },
+                    "end": {
+                        "line": 28,
+                        "column": null
+                    }
+                }
+            ]
+        },
+        "1": {
+            "loc": {
+                "start": {
+                    "line": 29,
+                    "column": 8
+                },
+                "end": {
+                    "line": 33,
+                    "column": null
+                }
+            },
+            "type": "if",
+            "locations": [
+                {
+                    "start": {
+                        "line": 29,
+                        "column": 8
+                    },
+                    "end": {
+                        "line": 33,
+                        "column": null
+                    }
+                },
+                {
+                    "start": {
+                        "line": 29,
+                        "column": 8
+                    },
+                    "end": {
+                        "line": 33,
+                        "column": null
+                    }
+                }
+            ]
+        },
+        "2": {
+            "loc": {
+                "start": {
+                    "line": 35,
+                    "column": 8
+                },
+                "end": {
+                    "line": 43,
+                    "column": null
+                }
+            },
+            "type": "switch",
+            "locations": [
+                {
+                    "start": {
+                        "line": 36,
+                        "column": 12
+                    },
+                    "end": {
+                        "line": 36,
+                        "column": 27
+                    }
+                },
+                {
+                    "start": {
+                        "line": 37,
+                        "column": 12
+                    },
+                    "end": {
+                        "line": 38,
+                        "column": 118
+                    }
+                },
+                {
+                    "start": {
+                        "line": 39,
+                        "column": 12
+                    },
+                    "end": {
+                        "line": 40,
+                        "column": 119
+                    }
+                },
+                {
+                    "start": {
+                        "line": 41,
+                        "column": 12
+                    },
+                    "end": {
+                        "line": 42,
+                        "column": 118
+                    }
+                }
+            ]
+        }
+    },
+    "s": {
+        "0": 1,
+        "1": 1,
+        "2": 1,
+        "3": 3,
+        "4": 3,
+        "5": 0,
+        "6": 0,
+        "7": 0,
+        "8": 0,
+        "9": 0,
+        "10": 0,
+        "11": 0,
+        "12": 0,
+        "13": 0,
+        "14": 1
+    },
+    "f": {
+        "0": 3,
+        "1": 0,
+        "2": 0
+    },
+    "b": {
+        "0": [
+            0,
+            0
+        ],
+        "1": [
+            0,
+            0
+        ],
+        "2": [
+            0,
+            0,
+            0,
+            0
+        ]
+    }
+}
\ No newline at end of file
diff --git a/packages/istanbul-lib-source-maps/test/testdata/switchBranchCoverageDataMapping.json b/packages/istanbul-lib-source-maps/test/testdata/switchBranchCoverageDataMapping.json
new file mode 100644
index 00000000..3258673d
--- /dev/null
+++ b/packages/istanbul-lib-source-maps/test/testdata/switchBranchCoverageDataMapping.json
@@ -0,0 +1,562 @@
+[
+    {
+        "start": {
+            "line": 3,
+            "column": 29
+        },
+        "end": {
+            "line": 3,
+            "column": 60
+        },
+        "mapped": {
+            "start": {
+                "line": 7,
+                "column": 0
+            },
+            "end": {
+                "line": 7,
+                "column": 54
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 4,
+            "column": 29
+        },
+        "end": {
+            "line": 4,
+            "column": 60
+        },
+        "mapped": {
+            "start": {
+                "line": 8,
+                "column": 0
+            },
+            "end": {
+                "line": 8,
+                "column": 54
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 5,
+            "column": 30
+        },
+        "end": {
+            "line": 5,
+            "column": 62
+        },
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+                "column": 0
+            },
+            "end": {
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+                "column": 56
+            }
+        }
+    },
+    {
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+            "column": 8
+        },
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+            "column": 45
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+            "start": {
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+                "column": 8
+            },
+            "end": {
+                "line": 16,
+                "column": 45
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 9,
+            "column": 8
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+            "column": 29
+        },
+        "mapped": {
+            "start": {
+                "line": 17,
+                "column": 8
+            },
+            "end": {
+                "line": 17,
+                "column": 29
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 12,
+            "column": 8
+        },
+        "end": {
+            "line": 12,
+            "column": 107
+        },
+        "mapped": {
+            "start": {
+                "line": 21,
+                "column": 8
+            },
+            "end": {
+                "line": 21,
+                "column": 110
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 15,
+            "column": 8
+        },
+        "end": {
+            "line": 18,
+            "column": 9
+        },
+        "mapped": {
+            "start": {
+                "line": 25,
+                "column": 8
+            },
+            "end": {
+                "line": 28,
+                "column": null
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 17,
+            "column": 12
+        },
+        "end": {
+            "line": 17,
+            "column": 24
+        },
+        "mapped": {
+            "start": {
+                "line": 27,
+                "column": 12
+            },
+            "end": {
+                "line": 27,
+                "column": 24
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 19,
+            "column": 8
+        },
+        "end": {
+            "line": 23,
+            "column": 9
+        },
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+                "column": 8
+            },
+            "end": {
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+                "column": null
+            }
+        }
+    },
+    {
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+            "column": 12
+        },
+        "end": {
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+        },
+        "mapped": {
+            "start": {
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+                "column": 12
+            },
+            "end": {
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+                "column": 114
+            }
+        }
+    },
+    {
+        "start": {
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+            "column": 8
+        },
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+            "line": 32,
+            "column": 9
+        },
+        "mapped": {
+            "start": {
+                "line": 35,
+                "column": 8
+            },
+            "end": {
+                "line": 43,
+                "column": null
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 27,
+            "column": 16
+        },
+        "end": {
+            "line": 27,
+            "column": 115
+        },
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+                "column": 16
+            },
+            "end": {
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+                "column": 118
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 29,
+            "column": 16
+        },
+        "end": {
+            "line": 29,
+            "column": 116
+        },
+        "mapped": {
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+                "column": 16
+            },
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+                "column": 119
+            }
+        }
+    },
+    {
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+        },
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+            "column": 115
+        },
+        "mapped": {
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+                "column": 16
+            },
+            "end": {
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+                "column": 118
+            }
+        }
+    },
+    {
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+            "column": 0
+        },
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+        "mapped": {
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+                "column": 0
+            },
+            "end": {
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+                "column": 21
+            }
+        }
+    },
+    {
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+        },
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+            "column": 5
+        },
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+            },
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+                "column": 16
+            }
+        }
+    },
+    {
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+        },
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+                "column": 64
+            },
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+            }
+        }
+    },
+    {
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+        },
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+        "mapped": {
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+                "column": 29
+            }
+        }
+    },
+    {
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+        },
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+                "column": 5
+            }
+        }
+    },
+    {
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+        },
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+            "column": 5
+        },
+        "mapped": {
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+                "column": 11
+            },
+            "end": {
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+                "column": 22
+            }
+        }
+    },
+    {
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+        },
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+            "column": 5
+        },
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+                "column": 73
+            },
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+                "column": 5
+            }
+        }
+    },
+    {
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+        },
+        "end": {
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+        },
+        "mapped": {
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+                "column": 8
+            },
+            "end": {
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+                "column": null
+            }
+        }
+    },
+    {
+        "start": {
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+            "column": 8
+        },
+        "end": {
+            "line": 23,
+            "column": 9
+        },
+        "mapped": {
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+                "column": 8
+            },
+            "end": {
+                "line": 33,
+                "column": null
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 24,
+            "column": 8
+        },
+        "end": {
+            "line": 32,
+            "column": 9
+        },
+        "mapped": {
+            "start": {
+                "line": 35,
+                "column": 8
+            },
+            "end": {
+                "line": 43,
+                "column": null
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 25,
+            "column": 12
+        },
+        "end": {
+            "line": 25,
+            "column": 27
+        },
+        "mapped": {
+            "start": {
+                "line": 36,
+                "column": 12
+            },
+            "end": {
+                "line": 36,
+                "column": 27
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 26,
+            "column": 12
+        },
+        "end": {
+            "line": 27,
+            "column": 115
+        },
+        "mapped": {
+            "start": {
+                "line": 37,
+                "column": 12
+            },
+            "end": {
+                "line": 38,
+                "column": 118
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 28,
+            "column": 12
+        },
+        "end": {
+            "line": 29,
+            "column": 116
+        },
+        "mapped": {
+            "start": {
+                "line": 39,
+                "column": 12
+            },
+            "end": {
+                "line": 40,
+                "column": 119
+            }
+        }
+    },
+    {
+        "start": {
+            "line": 30,
+            "column": 12
+        },
+        "end": {
+            "line": 31,
+            "column": 115
+        },
+        "mapped": {
+            "start": {
+                "line": 41,
+                "column": 12
+            },
+            "end": {
+                "line": 42,
+                "column": 118
+            }
+        }
+    }
+]
diff --git a/packages/istanbul-lib-source-maps/test/transformer.test.js b/packages/istanbul-lib-source-maps/test/transformer.test.js
index 6de8dc1f..d419f008 100644
--- a/packages/istanbul-lib-source-maps/test/transformer.test.js
+++ b/packages/istanbul-lib-source-maps/test/transformer.test.js
@@ -50,6 +50,34 @@ const testDataBackslash = {
     }
 };
 
+class MappingResolver {
+    constructor(mappingFile) {
+        this.mapping = require(mappingFile);
+    }
+
+    resolveMapping(sourceMap, location, filePath) {
+        const mapResult = this.mapping.find(
+            m =>
+                m.start.line == location.start.line &&
+                m.start.column == location.start.column &&
+                m.end.line == location.end.line &&
+                m.end.column == location.end.column
+        );
+
+        if (!mapResult) {
+            return null;
+        }
+
+        return {
+            source: filePath.replace('.js', '.ts'),
+            loc: {
+                start: mapResult.mapped.start,
+                end: mapResult.mapped.end
+            }
+        };
+    }
+}
+
 describe('transformer', () => {
     it('maps statement locations', async () => {
         const coverageMap = createMap({});
@@ -91,4 +119,25 @@ describe('transformer', () => {
         assert.equal(Object.keys(mapped.data).length, 1);
         assert.isDefined(mapped.data[testDataBackslash.coverageData.path]);
     });
+
+    it('correctly maps location for branch statements', async () => {
+        const switchBranchCoverageData = require('./testdata/switchBranchCoverageData.json');
+        const switchBranchCoverageDataExpectedResult = require('./testdata/switchBranchCoverageDataExpectedResult.json');
+        const mappingResolver = new MappingResolver(
+            './testdata/switchBranchCoverageDataMapping.json'
+        );
+
+        const coverageMap = createMap({});
+        coverageMap.addFileCoverage(switchBranchCoverageData);
+
+        const transformer = new SourceMapTransformer(file => ({ file }), {
+            getMapping: mappingResolver.resolveMapping.bind(mappingResolver)
+        });
+        const mapped = await transformer.transform(coverageMap);
+
+        assert.deepEqual(
+            mapped.fileCoverageFor('dummyFile.ts').data,
+            switchBranchCoverageDataExpectedResult
+        );
+    });
 });