所有原型的功能-Javascript

Question

I'm working on a video player with video.js. On this side I've got elements (volume, fullscreen, play, pause...) which are prototypes . On the other side I've got my functions parse() which is going to be use by all of the canvas prototypes (they come from different elements).

parse Function :

vjs.parseHex = function(c) {
    if(c.charAt(0) == "#") {
        return c.substring(1,7);
    } else if(c.substr(0,2) == "0x") {
        return c.substring(2,8);
    } else {
        return c;
    }
},

vjs.parseRed = function(c) {
    return parseInt((this.parseHex(c)).substring(0,2),16);
},

vjs.parseGreen = function(c) {
    return parseInt((this.parseHex(c)).substring(2,4),16);
},

vjs.parseBlue = function(c) {
    return parseInt((this.parseHex(c)).substring(4,6),16);
}

An exemple of my canvas prototype :

js.VolumeBar.prototype.drawSound = function(){
  .
  .
  .
}

I want that my parse functions are accessible by all of the different prototypes. Is that possible ? If yes, how can I do that?

Thank you for helping me, Léa.

Answer 1

It seems that vjs is a sort of Util namespace that contains a few functions that should be used in different places. As long as that is public it can be used anywhere:

vjs = {};
vjs.parseHex = function(c) { /*...*/ }
vjs.parseRed = function(c) { /*...*/ }


js.VolumeBar.prototype.drawSound = function(){
  vjs.parseRed(stuff);
}

Keep in mind that if you pass vjs.parseRed as a callback, it will be called with a different object as this than what you expect. You could rewrite it to either

• replace this with vjs :

  vjs.parseRed = function(c) { return parseInt((vjs.parseHex(c)).substring(0,2),16); }

• bind the functions when you pass them as parameters:

  doAsync(vjs.parseRed.bind(vjs));

• or just bind them when you define them:

  vjs.parseRed = function(c) { /*...*/ }.bind(vjs);