feat: add isStrBlank

DOC.md

@@ -8359,6 +8359,29 @@ Check if value is a string primitive.
 isStr('licia'); // -> true
 ```
 
+## isStrBlank 
+
+Check if string is blank.
+
+<details>
+<summary>Type Definition</summary>
+<pre>
+<code class="language-typescript">function isStrBlank(str: string): boolean;</code>
+</pre>
+</details>
+
+|Name  |Desc                   |
+|------|-----------------------|
+|str   |String to check        |
+|return|True if string is blank|
+
+```javascript
+isStrBlank('licia'); // -> false
+isStrBlank(''); // -> true
+isStrBlank('    '); // -> true
+isStrBlank('\r\n '); // -> true
+```
+
 ## isStream 
 
 Check if value is a Node.js stream.

DOC_CN.md

@@ -8352,6 +8352,29 @@ isSorted([3, 2, 1]); // -> false
 isStr('licia'); // -> true
 ```
 
+## isStrBlank
+
+检查字符串是否为空。
+
+<details>
+<summary>类型定义</summary>
+<pre>
+<code class="language-typescript">function isStrBlank(str: string): boolean;</code>
+</pre>
+</details>
+
+|参数名|说明|
+|-----|---|
+|str|要检查的字符串|
+|返回值|如果字符串为空，返回真|
+
+```javascript
+isStrBlank('licia'); // -> false
+isStrBlank(''); // -> true
+isStrBlank('    '); // -> true
+isStrBlank('\r\n '); // -> true
+```
+
 ## isStream
 
 检查值是否是 Node.js Stream 类型。

benchmark/isStrBlank.js

@@ -0,0 +1,19 @@
+const trim = util.trim;
+const randomId = util.randomId;
+const each = util.each;
+
+const tests = [
+    ' ',
+    randomId(1000),
+    ` ${randomId(1000)} `,
+    ` ${randomId(1000, ' \n\r\t\f\v')}`
+];
+
+benchmark({
+    trim() {
+        each(tests, test => trim(test) === '');
+    },
+    licia() {
+        each(tests, test => isStrBlank(test));
+    }
+});

cspell.json

@@ -238,6 +238,7 @@
     "isSet",
     "isSorted",
     "isStr",
+    "isStrBlank",
     "isStream",
     "isSymbol",
     "isTypedArr",

i18n/isStrBlank.md

@@ -0,0 +1,8 @@
+## CN
+
+检查字符串是否为空。
+
+|参数名|说明|
+|-----|---|
+|str|要检查的字符串|
+|返回值|如果字符串为空，返回真|

index.json

@@ -4034,6 +4034,20 @@
             "browser"
         ]
     },
+    "isStrBlank": {
+        "benchmark": true,
+        "dependencies": [],
+        "description": "Check if string is blank.",
+        "env": [
+            "node",
+            "browser",
+            "miniprogram"
+        ],
+        "test": [
+            "node",
+            "browser"
+        ]
+    },
     "isStream": {
         "dependencies": [
             "isObj",

src/isStrBlank.js

@@ -0,0 +1,40 @@
+/* Check if string is blank.
+ *
+ * |Name  |Desc                   |
+ * |------|-----------------------|
+ * |str   |String to check        |
+ * |return|True if string is blank|
+ */
+
+/* example
+ * isStrBlank('licia'); // -> false
+ * isStrBlank(''); // -> true
+ * isStrBlank('    '); // -> true
+ * isStrBlank('\r\n '); // -> true
+ */
+
+/* module
+ * env: all
+ */
+
+/* typescript
+ * export declare function isStrBlank(str: string): boolean;
+ */
+
+exports = function(str) {
+    for (let i = 0, len = str.length; i < len; i++) {
+        const c = str[i];
+        if (
+            c !== ' ' &&
+            c !== '\n' &&
+            c !== '\r' &&
+            c !== '\t' &&
+            c !== '\f' &&
+            c !== '\v'
+        ) {
+            return false;
+        }
+    }
+
+    return true;
+};

test/isStrBlank.js

@@ -0,0 +1,6 @@
+tests([
+    ['licia', false],
+    ['', true],
+    ['    ', true],
+    ['\r\n ', true]
+]);