The Symbol.toPrimitive
is a symbol that specifies a function valued property that is called to convert an object to a corresponding primitive value.
Symbol.toPrimitive
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Description
With the help of the Symbol.toPrimitive
property (used as a function value), an object can be converted to a primitive value. The function is called with a string argument hint
, which specifies the preferred type of the result primitive value. The hint
argument can be one of "number
", "string
", and "default
".
Property attributes of Symbol.toPrimitive |
|
---|---|
Writable | no |
Enumerable | no |
Configurable | no |
Examples
Modifying primitive values converted from an object
Following example describes how Symbol.toPrimitive
property can modify the primitive value converted from an object.
// An object without Symbol.toPrimitive property. var obj1 = {}; console.log(+obj1); // NaN console.log(`${obj1}`); // "[object Object]" console.log(obj1 + ''); // "[object Object]" // An object with Symbol.toPrimitive property. var obj2 = { [Symbol.toPrimitive](hint) { if (hint == 'number') { return 10; } if (hint == 'string') { return 'hello'; } return true; } }; console.log(+obj2); // 10 -- hint is "number" console.log(`${obj2}`); // "hello" -- hint is "string" console.log(obj2 + ''); // "true" -- hint is "default"
Specifications
Browser compatibility
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | Deno | Node.js | |
toPrimitive |
47
|
15
|
44
|
No
|
34
|
10
|
47
|
47
|
44
|
34
|
10
|
5.0
|
1.0
|
6.0.0
|
See also
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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toPrimitive