即时将简单值推入数组

Question

I want to be able to create an array with only one value inside of it on the fly without using a variable. This works with a variable:

var arr = [];
arr.push('test');
console.log(arr); // correctly logs ["test"]

But this does not:

console.log([].push('test')); // logs 1

Why does this log 1 instead of ["test"] ? Is this coerced into a boolean?

Answer 1

Array.prototype.push returns the new length of the array, not the pushed item nor the array it-self.

"I want to be able to create an array with only one value inside of it on the fly without using a variable"

const arr = ['test'];

 console.log(['test']);

Answer 2

Array.prototype.push()

The push() method adds one or more elements to the end of an array and returns the new length of the array .

In the first example you are first pushing the element in the array then log the array. But in the second example you are logging the returned result of push() .