我如何有效地原型Array或从Array重用代码？

Question

I built a parser and I would like to 'extend' the Array class in order to use the same functions but have not been successful with:

Array.prototype = new Parser()

I would like to create a function that would reuse the shift from the array without me having to add:

function() { return this.list.shift() }

Also I've been having some problems with the this identity so:

How can i effectively prototype Array or from Array to reuse code ?

function Parser() {
  this.get_info_colors = function() {
    return {
      'id': self.shift(),
      'name': self.shift(),
      'colors': self.get_colors()
    }
  }
  this.get_info_grad = function() {
    return {
      'id': self.shift(),
      'name': (self.shift() + '_grad'),
      'grad': self.shift()
    }
  }
  this.get_colors = function() {
    this.shift();
    var result = [],
        element;
    while(element != ']') {
      element = this.shift();
      result.push();
    }
    return element;
  }
  this.builder = function(factory) {
    this.shift();
    var result = [],
        element;
    while(element != ']') {
      result.push(factory());
    }
    return result;
  }
  this.color_builder = function() {
    return this.builder(this.get_info_colors);
  }
  this.grad_builder = function() {
    return this.builder(this.get_info_grad);
  }
}

Thanks in advance.

Answer 1

To extend Array , you need to extend its prototype, like this

function CustomArray() {}
CustomArray.prototype = Object.create(Array.prototype);
CustomArray.constructor = CustomArray;

And then you can add all your custom methods on the CustomArray 's prototype, like this

CustomArray.prototype.newMethod = function() {...}

Answer 2

我使用Array.prototype.parser = function(){ // your parser }

Answer 3

First of all, see this post:

Why is extending native objects a bad practice?

Second, do you want to extend Parser to derive methods of Array or vice versa? Basically it would be quite okay to have Parser derive methods from Array, but then your prototype assignment is wrong.

Parser.prototype = [];

Did you try it that way.

Regarding your issues with this the posted code isn't complete, is it?

EDIT : Some example:

function Parser() { this.__a = 1; }
Parser.prototype = [];
var a = new Parser;
a.length
// gives 0
a.push( 2 );
// gives 1
a.length
// gives 1
a.__a
// gives 1

EDIT 2 : Example for using constructor as given in comments:

function Parser() { 
  var args = [].slice.call( arguments );
  args.unshift( 0 ); 
  args.unshift( 0 ); 
  [].splice.apply( this, args ); 
}

Parser.prototype = [];

var c = new Parser( 1, 2, 3 )
c.length
// gives 3