“tipo de” Código de respuesta

tipo de js variable

// get type of variable

var number = 1
var string = 'hello world'
var dict = {a: 1, b: 2, c: 3}

console.log(typeof number) // number
console.log(typeof string) // string
console.log(typeof dict)   // object
Maxime Laplace

Tipo de JavaScript

//typeof() will return the type of value in its parameters.
//some examples of types: undefined, NaN, number, string, object, array

//example of a practical usage
if (typeof(value) !== "undefined") {//also, make sure that the type name is a string
  	//execute code
}
The Amateur

tipo de

// Numbers
typeof 37 === 'number';
typeof 3.14 === 'number';
typeof(42) === 'number';
typeof Math.LN2 === 'number';
typeof Infinity === 'number';
typeof NaN === 'number'; // Despite being "Not-A-Number"
typeof Number('1') === 'number';      // Number tries to parse things into numbers
typeof Number('shoe') === 'number';   // including values that cannot be type coerced to a number

typeof 42n === 'bigint';

// Strings
typeof '' === 'string';
typeof 'bla' === 'string';
typeof `template literal` === 'string';
typeof '1' === 'string'; // note that a number within a string is still typeof string
typeof (typeof 1) === 'string'; // typeof always returns a string
typeof String(1) === 'string'; // String converts anything into a string, safer than toString

// Booleans
typeof true === 'boolean';
typeof false === 'boolean';
typeof Boolean(1) === 'boolean'; // Boolean() will convert values based on if they're truthy or falsy
typeof !!(1) === 'boolean'; // two calls of the ! (logical NOT) operator are equivalent to Boolean()

// Symbols
typeof Symbol() === 'symbol'
typeof Symbol('foo') === 'symbol'
typeof Symbol.iterator === 'symbol'

// Undefined
typeof undefined === 'undefined';
typeof declaredButUndefinedVariable === 'undefined';
typeof undeclaredVariable === 'undefined';

// Objects
typeof {a: 1} === 'object';

// use Array.isArray or Object.prototype.toString.call
// to differentiate regular objects from arrays
typeof [1, 2, 4] === 'object';

typeof new Date() === 'object';
typeof /regex/ === 'object'; // See Regular expressions section for historical results

// The following are confusing, dangerous, and wasteful. Avoid them.
typeof new Boolean(true) === 'object';
typeof new Number(1) === 'object';
typeof new String('abc') === 'object';

// Functions
typeof function() {} === 'function';
typeof class C {} === 'function';
typeof Math.sin === 'function';

// for Date and Regexp objects use instance of
if (dateObj instanceof Date) {}
if (object instanceof RegExp) {}
SubZ390

nodo JS Tipo de verificación de variable

if (typeof i != "number") {
    console.log('This is not number');
}
Plain Piranha

Número de typeof js

console.log(typeof 93);
// Output = "number"

console.log(typeof 'Maximum');
// Output = 'string'

console.log(typeof false);
// Output = "boolean"

console.log(typeof anUndeclaredVariable);
// Output = "undefined"
aMax

typeof JavaScript

var miFuncion = new Function("5+2")
var forma = "redonda"
var tamano = 1
var hoy = new Date()


typeof miFuncion === 'function'
typeof forma === 'string'
typeof tamano === 'number'
typeof hoy === 'object'
typeof noExiste === 'undefined'
Grieving Gharial

Respuestas similares a “tipo de”

Preguntas similares a “tipo de”

Explore las respuestas de código populares por idioma

Explorar otros lenguajes de código