don't-use-array-foreach-use-for-instead
slower
https://coderwall.com/p/kvzbpa/don-t-use-array-foreach-use-for-instead
https://jsperf.com/fast-array-foreach
// OK
console.time(`for 计时器`);
console.timeEnd(`for 计时器`);
// Bad
console.time(`for 计时器 begin`);
console.timeEnd(`for 计时器 end`);
console.time(`for 计时器`);
for (let i = 0; i < 10000; i++) {
let result = i ** 3;
console.log(`result = ${result}`);
}
console.timeEnd(`for 计时器`);
// for 计时器: 1744.241943359375ms
const a = [];
for (let i = 0; i < 10000; i++) {
a[i] = i;
}
console.time(`forEach 计时器`);
a.forEach((i) => {
let result = i ** 3;
console.log(`result = ${result}`);
})
console.timeEnd(`forEach 计时器`);
// forEach 计时器: 2139.04296875ms
js console 性能测试
https://yq.aliyun.com/ziliao/174827
http://www.cnblogs.com/cilong/articles/1845282.html
https://www.javascriptcn.com/read-2807.html
http://www.jb51.net/article/64971.htm
/*
console.trace()用来追踪函数的调用过程。
对于前端开发人员，在开发过程中经常需要监控某些表达式或变量的值，如果使用用 debugger 会显得过于笨重，最常用的方法是会将值输出到控制台上方便调试。
console.table(people);
console.time()和console.timeEnd()
console.time('计时器');
for (var i = 0; i < 1000; i++) {
for (var j = 0; j < 1000; j++) {}
}
console.timeEnd('计时器');
console.profile()
借助控制台以及console.profile()方法我们可以很方便地监控运行性能。
console.profile('性能分析');
// parent();
console.profileEnd();
*/
attributes
https://developer.mozilla.org/en-US/docs/Web/API/Element/attributes
https://developer.mozilla.org/en-US/docs/Web/API/Element/hasAttributes
https://developer.mozilla.org/en-US/docs/Web/API/Element/hasAttribute
Uint8Array
let arr = new Uint8Array(10).map((item, i) => item = i);
// Uint8Array(10) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
let arr = new Uint8Array(10).map((item, i) => item = i + 1);
// Uint8Array(10) [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
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