Angular equivalent of jQuery $.map?

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难免孤独
难免孤独 2021-01-03 18:02

I\'m transitioning from relying on jQuery to building apps in AngularJS. It\'s recommended in a number of places to not mix jQuery and Angular code.

One thi

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  • 2021-01-03 18:29

    Check here: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/map

    Mozilla has supplied an Array.map polyfill for unsupported browsers

    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;
      };      
    }
    
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  • 2021-01-03 18:41

    No, there is no equivalent in Angular. And as you discovered, no you don't need to fall back to writing imperative code.

    Instead, just use the map function that is built directly into JavaScript. If you need to support IE8, insert the polyfill at the beginning of your scripts.

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