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Jun 18, 2012 · For example, the toString prototype does not exist on undefined variables, but you can cast undefined to a string using the other two methods: var foo; var myString1 = String(foo); // "undefined" as a string var myString2 = foo + ''; // "undefined" as a string var myString3 = foo.toString(); // throws an exception
As @RobG pointed out, the output of Date.prototype.toString() is implementation-dependent, so for international or non-browser implementations, just test the output to be sure it works right in your JavaScript engine.
Apr 14, 2020 · If a given object implements a toString() method, then the function should use it. Otherwise, the function can rely on what the JavaScript implementation offers. What I come up with is like this: var convert = function (arg) { return (new String(arg)).valueOf(); }
If toString() is not overridden in a custom object: per documentation 15.2.4.2 Object.prototype.toString ( ) # Ⓣ Ⓔ Ⓡ When the toString method is called, the following steps are taken: If the this value is undefined, return "[object Undefined]". If the this value is null, return "[object Null]".
All misplaced ideas on abuse. Personally I do not see why JavaScript needs to go down the route its going, it was never meant to be a program tightly bound and made more complex than it is already. If you want to be bound then make a compiler for javascript. –
In your cases, the addition operator calls the toString method of the object. From the specs: If Type(lprim) is String or Type(rprim) is String, then. a. Return the String that is the result of concatenating ToString(lprim) followed by ToString(rprim). However, this native method can be overridden, which you've done* in the first snippet.
num = num.toString() Note: You can't directly call toString() on a number. 2.toString() will throw Uncaught SyntaxError: Invalid or unexpected token. (The performance test results are given by @DarckBlezzer in his answer)
Jul 28, 2011 · 1. toString ( ) And that's an illegal sequence of tokens. It's object method, instead of object . method. In the working versions in @Joey's answer, the braces prevent the tokenizer from treating the dot as part of the number literal instead of as a separate token, as does writing: 1.0.toString() or. 1..toString()
Oct 15, 2010 · String(value) should have the same result as value.toString() in every case, except for values without properties like null or undefined. ''+value will produce the same result. Share
There's no difference. I think that they used the toString function just to emphasize that it exists. Every object in javascript has a toString function, because it's defined on Object's prototype, like explained here. The difference is that the String type overrides the original toString function, otherwise the result would be "[object String]".
