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javascriptfunctionparameters

Pass a JavaScript function as parameter

How do I pass a function as a parameter without the function executing in the "parent" function or using eval()? (Since I've read that it's insecure.)

I have this:

addContact(entityId, refreshContactList());

It works, but the problem is that refreshContactList fires when the function is called, rather than when it's used in the function.

I could get around it using eval(), but it's not the best practice, according to what I've read. How can I pass a function as a parameter in JavaScript?

Solution

  • You just need to remove the parenthesis:

    addContact(entityId, refreshContactList);

    This then passes the function without executing it first.

    Here is an example:

    function addContact(id, refreshCallback) {
    refreshCallback();
    // You can also pass arguments if you need to
    // refreshCallback(id);
}

function refreshContactList() {
    alert('Hello World');
}

addContact(1, refreshContactList);