javascript find type of variable
> typeof "foo"
"string"
> typeof true
"boolean"
> typeof 42
"number"
if(typeof bar === 'number') {
//whatever
}
javascript find type of variable
> typeof "foo"
"string"
> typeof true
"boolean"
> typeof 42
"number"
if(typeof bar === 'number') {
//whatever
}
check data type in js
typeof("string"); //string
typeof(123); //number
check data type in js
typeof("iAmAString");//This should return 'string'
//NO camelCase, as it is a JS Keyword
javascript typeof
exports.is = (data) => {
const isArray = Array.isArray(data) && 'array'
const isObject = data == {} && 'object'
const isNull = data == null && 'null'
const isGrouping = isArray || isObject || isNull
const isCheck = !isGrouping ? typeof data : isGrouping
const isTypeData = ['number','string','array','symbol','object','undefined','null','function', 'boolean']
const isMatch = isTypeData.indexOf(isCheck)
const isResult = isTypeData[isMatch]
return isResult
}
javascript check type of variable var
> typeof "foo"
"string"
> typeof true
"boolean"
> typeof 42
"number"
js null is object typeof
In the first implementation of JavaScript, JavaScript values were represented
as a type tag and a value. The type tag for objects was 0. null was represented
as the NULL pointer (0x00 in most platforms). Consequently, null had 0 as type
tag, hence the "object" typeof return value. (reference)
A fix was proposed for ECMAScript (via an opt-in), but was rejected.
It would have resulted in typeof null === 'null'.
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