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Gerhut/curly.js

Created June 19, 2014 03:56
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{}的二义性
Raw
curly.js
{} + [] // => {}; +[] => 0
[] + {} // => '' + '[object Object]' => '[object Object]'
{} + [] == [] + {} // => {}; 0 == '[object Object]' => false
({} + [] == [] + {}) // => '[object Object]' + '' == '' + '[Object Object]' => true
/*
知识点：
1. {}放在语句开头的时候，被当做括代码的大括号；不在开头的时候，被当做括对象的大括号。
2. 单目运算符 `+ val` 就是把val强转为数字
3. +两边只要有非数字，就把两边转为字符串，做字符串连接。
4. 空数组转为空字符串，空对象转为'[object Object]'
*/
@mingyun

mingyun commented Jun 21, 2014

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({}) + [] '[object Object]'
{}+{} NaN

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