Call function with “this”

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别跟我提以往
别跟我提以往 2020-12-16 01:37
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  • 2020-12-16 02:03

    Rob's answer is the best answer for your problem, but I wanted to address something that you wrote in your original question:

    I know I can pass this as an argument to handleOnClickConfirmed, but some of my code already uses handleOnClickConfirmed and I don't want to have to rewrite those calls.

    JavaScript parameters are always optional, as far as the interpreter is concerned. For example if you have the function:

    function MyFunction(paramA, paraB) {
      // do nothing
    }
    

    All of these calls will execute without error:

    MyFunction(1,2);
    MyFunction(1);
    MyFunction();
    

    So you could modify handleOnClickConfirmed to accept what would essentially be an optional parameter. Like so:

    function handleOnClickConfirmed(context) {
      context = context || this;
      // use context instead of 'this' through the rest of your code
    }
    

    Again, in this particular case, the call function is the best solution. But the technique I outlined above is a good one to have in your toolbox.

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  • 2020-12-16 02:15

    The following ought to do it:

    function handleOnClick() {
        if( confirm( "Sure?" ) ) {
            return handleOnClickConfirmed.call( this );
        }
        return false;
    }
    

    The call() function attached to Function objects is designed to allow this; calling a function with a desired context. It's an extremely useful trick when setting up event handlers that call back into functions within other objects.

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