IE兼容性----解决findIndex

 // 兼容ie数组没有findIndex方法
        if (!Array.prototype.findIndex) {
          Object.defineProperty(Array.prototype, 'findIndex', {
            value: function(predicate:any) {
             // 1. Let O be ? ToObject(this value).
              if (this == null) {
                throw new TypeError('"this" is null or not defined');
              }
        
              var o = Object(this);
        
              // 2. Let len be ? ToLength(? Get(O, "length")).
              var len = o.length >>> 0;
        
              // 3. If IsCallable(predicate) is false, throw a TypeError exception.
              if (typeof predicate !== 'function') {
                throw new TypeError('predicate must be a function');
              }
        
              // 4. If thisArg was supplied, let T be thisArg; else let T be undefined.
              var thisArg = arguments[1];
        
              // 5. Let k be 0.
              var k = 0;
        
              // 6. Repeat, while k < len
              while (k < len) {
                // a. Let Pk be ! ToString(k).
                // b. Let kValue be ? Get(O, Pk).
                // c. Let testResult be ToBoolean(? Call(predicate, T, « kValue, k, O »)).
                // d. If testResult is true, return k.
                var kValue = o[k];
                if (predicate.call(thisArg, kValue, k, o)) {
                  return k;
                }
                // e. Increase k by 1.
                k++;
              }
        
              // 7. Return -1.
              return -1;
            }
          });
        }