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68 lines
1.8 KiB
68 lines
1.8 KiB
export default function isEqual(a, b) {
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//如果a和b本来就全等
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if (a === b) {
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//判断是否为0和-0
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return a !== 0 || 1 / a === 1 / b;
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}
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//判断是否为null和undefined
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if (a == null || b == null) {
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return a === b;
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}
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//接下来判断a和b的数据类型
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var classNameA = toString.call(a),
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classNameB = toString.call(b);
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//var classNameA = typeof(a), (兼容IE的写法)
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//classNameB = typeof(b);
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//如果数据类型不相等，则返回false
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if (classNameA !== classNameB) {
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return false;
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}
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if (a instanceof Date) {
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classNameA = '[object Date]';
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}
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//如果数据类型相等，再根据不同数据类型分别判断
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switch (classNameA) {
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case '[object RegExp]':
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case '[object String]':
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case 'string':
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//进行字符串转换比较
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return '' + a === '' + b;
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case 'number':
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case '[object Number]':
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//进行数字转换比较,判断是否为NaN
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if (+a !== +a) {
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return +b !== +b;
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}
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//判断是否为0或-0
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return +a === 0 ? 1 / +a === 1 / b : +a === +b;
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case '[object Date]':
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case '[object Boolean]':
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case 'boolean':
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return +a === +b;
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}
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//如果是对象类型
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if (classNameA == '[object Object]' || classNameA == 'object') {
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//获取a和b的属性长度
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var propsA = Object.getOwnPropertyNames(a),
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propsB = Object.getOwnPropertyNames(b);
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if (propsA.length != propsB.length) {
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return false;
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}
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for (var i = 0; i < propsA.length; i++) {
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var propName = propsA[i];
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//如果对应属性对应值不相等，则返回false
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if (a[propName] !== b[propName]) {
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return false;
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}
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}
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return true;
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}
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//如果是数组类型
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if (classNameA == '[object Array]') {
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if (a.toString() == b.toString()) {
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return true;
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}
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return false;
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}
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}
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