feat: ability to do arbitrary string literals (#73)

Used for when using values from the configuration file for creating values in the editor.

For example, being able to provide a preview url with a param for the workspace: `https://project-${workspace}.domain.com/`

src/ts/utility/stringLiteral.test.ts

@@ -0,0 +1,13 @@
+import {interpolate} from './stringLiteral';
+import test from 'ava';
+
+test('correctly interpolates text with params', t => {
+  t.is(interpolate({foo: 'bar'}, 'test ${foo}'), 'test bar');
+  t.is(interpolate({foo: 'bar'}, 'test ${foo} ${foo.length}'), 'test bar 3');
+});
+
+test('error with interpolates with unknown param', t => {
+  t.throws(() => {
+    interpolate({foo: 'bar'}, 'test ${foo} ${bar}');
+  });
+});

src/ts/utility/stringLiteral.ts

@@ -0,0 +1,21 @@
+/**
+ * Used with normal input strings to provide values to interpolate using a
+ * set of params.
+ *
+ * ```js
+ * const template = 'Example text: ${text}';
+ * const result = interpolate({
+ *   text: 'Foo bar'
+ * }, template);
+ * // Example text: Foo bar
+ * ```
+ *
+ * @param params Params to be used in the interpolate.
+ * @param value Normal string value to interpolate.
+ * @returns String literal interpolated string.
+ */
+export function interpolate(params: Record<string, any>, value: string) {
+  const names = Object.keys(params);
+  const vals = Object.values(params);
+  return new Function(...names, `return \`${value}\`;`)(...vals);
+}