javascript - Construct function from strings -

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• javascript property access: dot notation vs. brackets? 10 answers

i wondering if possible. let's use 'canvas' example:

(function(){  function canvas(canvas){    this.canvas = document.queryselector('#canvas');    this.ctx = this.canvas.getcontext('2d');    this.testmethod('fillrect',[10,10,10,10]);  }  canvas.prototype.testmethod = function(method,params){  this.method = method;  this.params = params;    this.ctx.method.apply(this.ctx, params);    }  var canvas = new canvas();  })()

<canvas id='canvas' width=400 height=400></canvas>

of course doesn't work wonder if it's possible dynamically construct functions in way. achive sort of user interface input method name , parameters , executed in specific context (canvasrenderingcontext2d in particular example)

try changing line

this.ctx.method.apply(this.ctx, params); 

to

this.ctx[method].apply(this.ctx, params); 

since canvas's property ( value function) name stored in variable.

for example, if object is

var obj = {  a: function(){console.log(1)} } 

you can invoke

obj.a();  

or if have

var b = "a"; obj[b]();