Array数组方法

forEach

  Array.prototype.c_forEach = function(callback){
      for(let i=0;i<this.length;i++){
          callback(this[i],i,this)
      }
  }

map

  Array.prototype.c_map = function(callback){
      let result = [];
      for(let i=0;i<this.length;i++){
          result.push(callback(this[i],i,this));
      }
      return result;
  }

every

  Array.prototype.c_every = function(callback){
      for(let i=0;i<this.length;i++){
          if(!callback(this[i],i,this)){
              return false
          }
      }
      return true
  }

some

  Array.prototype.c_some = function(callback){
      for(let i=0;i<this.length;i++){
          if(callback(this[i],i,this)){
              return true
          }
      }
      return false
  }

reduce

 Array.prototype.c_reduce = function (callback, ...args) {
      let start = 0,
        pre;
      if (args.length) {
        pre = args[0];
      } else {
        pre = this[0];
        start = 1;
      }
      for (let i = start; i < this.length; i++) {
        pre = callback(pre, this[i], i, this);
      }
      return pre;
    };

find

    Array.prototype.c_find = function (callback) {
      for (let i = 0; i < this.length; i++) {
        if (callback(this[i], i, this)) {
          return this[i];
        }
      }
      return undefined;
    };

findIndex

    Array.prototype.c_findIndex = function (callback) {
      for (let i = 0; i < this.length; i++) {
        if (callback(this[i], i, this)) {
          return i
        }
      }
      return -1;
    };

fill

    Array.prototype.c_fill = function (value, start = 0, end) {
      end = end || this.length;
      for (let i = start; i < end; i++) {
        this[i] = value;
      }
      return this;
    };

includes

    Array.prototype.c_includes = function (value, start = 0) {
      if (start < 0) start = start + this.length;
      let isNaN = Number.isNaN(value);
      for (let i = start; i < this.length; i++) {
        if (this[i] === value || (isNaN && Number.isNaN(this[i]))) {
          return true;
        }
      }
      return false;
    };

join

    Array.prototype.c_join = function (value = ",") {
      let result = "";
      for (let i = 0; i < this.length; i++) {
        result = i === 0 ? `${result}${this[i]}` : `${result}${value}${this[i]}`;
      }
      return result;
    };