lodash笨方法实现之路

最新推荐文章于 2024-01-18 23:10:45 发布

原创最新推荐文章于 2024-01-18 23:10:45 发布 · 410 阅读

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本文将带你逐步探索 lodash 框架的源码实现，通过理解其基础功能的底层逻辑，深入学习 JavaScript 工具库的构建技巧。

// _.chunk(array, [size=1])
function chunk(array, num) {
var arr = []
for (var i = 0; i < array.length; i += num) {
arr.push(array.slice(i, i + num))
}
return arr
}
var arr = [1, 2, 3, 4, 5]
console.log(chunk(arr, 0))

·源码

function chunk(array, size, guard) {
      if ((guard ? isIterateeCall(array, size, guard) : size === undefined)) {
        size = 1;
      } else {
        size = nativeMax(toInteger(size), 0);
      }
      var length = array == null ? 0 : array.length;
      if (!length || size < 1) {
        return [];
      }
      var index = 0,
          resIndex = 0,
          result = Array(nativeCeil(length / size));

      while (index < length) {
        result[resIndex++] = baseSlice(array, index, (index += size));
      }
      return result;
    }

// _.compact(array)
// Creates an array with all falsey values removed. The values false, null, 0, "", undefined, and NaN are falsey.
function compact(array) {
    var arr = []
    for (var i = 0; i < array.length; i++) {
        if (array[i]) {
            arr.push(array[i])
        }
    }
    return arr
}
var arr = [1, 2, 3, 4, 5, false, NaN, 0, 99]
console.log(compact(arr))