@gmod/jbrowse/src/JBrowse/Util/FastPromise.js

JBrowse - client-side genome browser

/**
 * Very minimal and fast implementation of a promise, used in
 * performance-critical code.  Dojo Deferred is too heavy for some
 * uses.
 */

define([
       ],
       function(
       ) {

var fastpromise = function() {
    this.callbacks = [];
};

fastpromise.prototype.then = function( callback ) {
    if( 'value' in this )
        callback( this.value );
    else
        this.callbacks.push( callback );
};

fastpromise.prototype.resolve = function( value ) {
    this.value = value;
    var c = this.callbacks;
    delete this.callbacks;
    for( var i = 0; i<c.length; i++ )
        c[i]( this.value );
};

return fastpromise;
});