Is it possible to convert an array in JavaScript into a function argument sequence? Example:
run({ "render": [ 10, 20, 200, 200 ] });
function run(calls) {
var app = .... // app is retrieved from storage
for (func in calls) {
// What should happen in the next line?
var args = ....(calls[func]);
app[func](args); // This is equivalent to app.render(10, 20, 200, 200);
}
}
Yes. In current versions of JS you can use:
app[func]( ...args );
Users of ES5 and older will need to use the .apply() method:
app[func].apply( this, args );
Read up on these methods at MDN:
window.document.execCommand.apply(window,["insertHorizontalRule",false])
window.document as the first argument, not just window: window.document.execCommand.apply(window.document, ... )
window actually makes no sense in non-browser JavaScript frameworks such as NodeJS, therefore I'd suggest removing it from the answer.
f(...[1,2,3]).var args = [ 'p0', 'p1', 'p2' ];
function call_me (param0, param1, param2 ) {
// ...
}
// Calling the function using the array with apply()
call_me.apply(this, args);
And here a link to the original post that I personally liked for its readability
document.body.setAttribute.apply( this, ["foo", "bar"] ); I need to send variable arguments to various object methods with different argument requirements. Quick edit: Apparently this has to be document.body, or whatever the parent is
Only a void function can be called with the 'new' keywordapp[func].apply(this, args);
You might want to take a look at a similar question posted on Stack Overflow. It uses the .apply() method to accomplish this.
@bryc - yes, you could do it like this:
Element.prototype.setAttribute.apply(document.body,["foo","bar"])
But that seems like a lot of work and obfuscation compared to:
document.body.setAttribute("foo","bar")
