How to determine whether it is a character in javascript

How to judge whether it is a character in JavaScript: 1. Judge by "typeof(str)=='string'"; 2. Use the js native function "Object.prototype.toString" to judge.

The operating environment of this article: windows7 system, javascript version 1.8.5, Dell G3 computer.

js determines whether it is a string

determines whether it is a string:

1 Basic method:

typeof(str)=='string'

Simple and nothing What to say

2 Use js native functions:

Object.prototype.toString  // ƒ toString() { [native code] }
Object.prototype.toString.call(str)=="[object String]"

(1) Execute toString in this (context) of Object.prototype The native function will print out the environment variable type inside.

Object.prototype.toString() -->执行结果-->"[object Object]"

(2) If we change this (context), we can print out the current environment variable type and judge based on this type.

Object.prototype.toString.call(str) -->执行结果-->"[object String]"

[Recommended learning: javascript advanced tutorial]

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