How to pass context to anonymous function?

Question

There are some function, thats do something long work and its provides callback.

someFunc: function(argument, callback, context) {
  // do something long

  // c         


        

Answer 1

Use Function.prototype.call to invoke a function and manually set the this value of that function.

someFunc: function(argument, callback, context) {
    callback.call(context); // call the callback and manually set the 'this'
}

Now your callback has the expected this value.

someFunc('bla-bla', function () {
  // now 'this' is what you'd expect
    this.anotherFunc();
}, this);

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Of course you can pass arguments like normal in the .call invocation.

callback.call(context, argument);