hasClass 测试

hasClass.js

var some = Array.prototype.some;

function hasClass1(name){
    if (!name) {
        return false
    }

    return some.call(this, function(el){
        return this.test(el.className)
    }, new RegExp('(^|\\s)' + name + '(\\s|$)'));
}

function hasClass2(name){
    if (!name) {
        return false
    }
    
    return some.call(this, function(el){
        return (' ' + el.className + ' ').indexOf(this) > -1
    }, ' ' + name + ' ');
}


// test demos.

var nodes = [{className:'aa bb'}, {className:'bb cc'}, {className:' dd ee ff '}];

var ret1 = hasClass1.call(nodes, 'aa');
var ret2 = hasClass2.call(nodes, 'aa');
console.log(ret1, ret2);

var n = 1e7;

console.time('reg');
for(var i=0; i<n; i++) {
    hasClass1.call(nodes, 'aa')
}
console.timeEnd('reg');

console.time('str');
for(var i=0; i<n; i++) {
    hasClass2.call(nodes, 'aa')
}
console.timeEnd('str');