EN
JavaScript - how to check if value is object?
14 points
The first important thing is what is primitive type in JavaScript?
Primitive type literals:
0,1,2,-4,NaN,+Infinity,-Infinity, etc.'abc','', etc.true/falseundefinednull- special case, but we treat it as not defined object too
Everything else is object type!
In the below code shows how to check if value is object.
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function isObject(value) {2
return value === Object(value);3
}4
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// Usage example:7
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console.log( isObject(null) ); // false9
console.log( isObject(undefined) ); // false10
console.log( isObject(false) ); // false11
console.log( isObject(true) ); // false12
console.log( isObject(0) ); // false13
console.log( isObject(1) ); // false14
console.log( isObject(NaN) ); // false15
console.log( isObject(+Infinity) ); // false16
console.log( isObject('') ); // false17
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console.log( isObject([ ]) ); // true19
console.log( isObject({ }) ); // true20
console.log( isObject(function(){ }) ); // true21
console.log( isObject(new Number(1)) ); // true22
console.log( isObject(Object.prototype) ); // true23
console.log( isObject(Object.create(null)) ); // true
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function isObject(value) {2
if (value == null) { // null or undefined3
return false;4
}5
var type = typeof value;6
return type === 'function' || type === 'object';7
}8
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// Usage example:11
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console.log( isObject(null) ); // false13
console.log( isObject(undefined) ); // false14
console.log( isObject(false) ); // false15
console.log( isObject(true) ); // false16
console.log( isObject(0) ); // false17
console.log( isObject(1) ); // false18
console.log( isObject(NaN) ); // false19
console.log( isObject(+Infinity) ); // false20
console.log( isObject('') ); // false21
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console.log( isObject([ ]) ); // true23
console.log( isObject({ }) ); // true24
console.log( isObject(function(){ }) ); // true25
console.log( isObject(new Number(1)) ); // true26
console.log( isObject(Object.prototype) ); // true27
console.log( isObject(Object.create(null)) ); // true
