角度相当于jQuery $ .map？

Question

我正在从依赖jQuery过渡到在AngularJS中构建应用程序.我们建议在一些地方,以不混合jQuery和角码.

我想念的一件事是数组的jQuery $ .map函数.我知道这可以使用本机Javascript 映射函数重写,但并未在所有浏览器中实现(特别是IE <v9).

那么,是否有一个Angular等价物,或者我应该回到写作for (var x = 0; x < foo; x += 1) {...}所以我可以停止包含jQuery？

更新有时您只需知道要搜索的内容即可.Bergie说'寻找polyfills'.这是一个参考指南(来自Modernizr工作人员),用于在旧版浏览器上使用现代代码的大量资源:HTML5 Cross Browser Polyfills

Answer 1

请点击此处:https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/map

Mozilla为不支持的浏览器提供了Array.map polyfill

if (!Array.prototype.map) {
  Array.prototype.map = function(callback, thisArg) {

    var T, A, k;

    if (this == null) {
      throw new TypeError(" this is null or not defined");
    }

    // 1. Let O be the result of calling ToObject passing the |this| value as the argument.
    var O = Object(this);

    // 2. Let lenValue be the result of calling the Get internal method of O with the argument "length".
    // 3. Let len be ToUint32(lenValue).
    var len = O.length >>> 0;

    // 4. If IsCallable(callback) is false, throw a TypeError exception.
    // See: http://es5.github.com/#x9.11
    if (typeof callback !== "function") {
      throw new TypeError(callback + " is not a function");
    }

    // 5. If thisArg was supplied, let T be thisArg; else let T be undefined.
    if (thisArg) {
      T = thisArg;
    }

    // 6. Let A be a new array created as if by the expression new Array(len) where Array is
    // the standard built-in constructor with that name and len is the value of len.
    A = new Array(len);

    // 7. Let k be 0
    k = 0;

    // 8. Repeat, while k < len
    while(k < len) {

      var kValue, mappedValue;

      // a. Let Pk be ToString(k).
      //   This is implicit for LHS operands of the in operator
      // b. Let kPresent be the result of calling the HasProperty internal method of O with argument Pk.
      //   This step can be combined with c
      // c. If kPresent is true, then
      if (k in O) {

        // i. Let kValue be the result of calling the Get internal method of O with argument Pk.
        kValue = O[ k ];

        // ii. Let mappedValue be the result of calling the Call internal method of callback
        // with T as the this value and argument list containing kValue, k, and O.
        mappedValue = callback.call(T, kValue, k, O);

        // iii. Call the DefineOwnProperty internal method of A with arguments
        // Pk, Property Descriptor {Value: mappedValue, : true, Enumerable: true, Configurable: true},
        // and false.

        // In browsers that support Object.defineProperty, use the following:
        // Object.defineProperty(A, Pk, { value: mappedValue, writable: true, enumerable: true, configurable: true });

        // For best browser support, use the following:
        A[ k ] = mappedValue;
      }
      // d. Increase k by 1.
      k++;
    }

    // 9. return A
    return A;
  };      
}

Answer 2

不,Angular没有相应的东西.正如您所发现的那样,不需要回到编写命令式代码.

相反,只需使用map直接构建到JavaScript中的函数即可.如果需要支持IE8,请在脚本的开头插入polyfill.