函数 forEach

遍历数组，并不完全等同 Array.prototype.forEach，该forEach支持中断，支持类似Python的for else功能

Python的for else hack写法

try {
  [1, 2, 3, 4, 5].forEach((item, index) => {
    /* do something */
    if (index === 2 && item === 3) {
      // break;
      throw new Error('break');
    }
  });
  /* do else */
} catch (e: any) {
  if (e.message !== 'break') throw e;
}
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示例

const arr1 = [1, 2, 3];
let isDone = forEach(arr1, (_v, k) => (arr1[k] = k));
isEqual(arr1, [0, 1, 2]); // true
isDone; // true

// ArrayLike
isDone = forEach({ 0: 1, 1: 2, length: 2 }, (_v, k) => (arr1[k] = k + k));
isEqual(arr1, [0, 2, 2]); // true
isDone; // true

isDone = forEach(arr1, (_v, k) => {
  arr1[k] = k + 1;
  return k !== 1;
});
isDone; // false
isEqual(arr1, [1, 2, 2]); // true

let elseCount = 0;
isDone = forEach(
  arr2,
  (v, k) => (arr2[k] = 'a' + v),
  () => elseCount++, // 完整遍历以后会执行该方法
);
isDone; // true
elseCount; // 1
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