模板字符串和标签模板
我要评论const getcourselist = function() {
// ajax
return {
status: true,
msg: '获取成功',
data: [{
id: 1,
title: 'vue 入门',
date: 'xxxx-01-09'
}, {
id: 2,
title: 'es6 入门',
date: 'xxxx-01-10'
}, {
id: 3,
title: 'react入门',
date: 'xxxx-01-11'
}]
}
};
const { data: listdata, status, msg } = getcourselist();
function foo(val) {
return val.replace('xxxx', '2020');
}
if (status) {
let arr = [];
listdata.foreach(function({ date, title }) {
arr.push(
`
<li>
<span>${ `课程名: ${ title }` }</span>
<span>${ foo(date) }</span>
</li>
`
);
});
let ul = document.createelement('ul');
ul.innerhtml = arr.join('');
document.body.appendchild(ul);
} else {
alert(msg);
}
padstart padend
{
let str = 'i';
// 插入在5的位置
let str1 = str.padstart(5, 'mooc');
console.log(str1);
// 倒序插入在5的位置
let str2 = str.padend(5, 'mooc');
console.log(str2);
}
repeat
{
function repeat(str, num) {
return new array(num + 1).join(str);
}
console.log(repeat('s', 3));
}
startswith endswith
{
const str = 'a promise is a promsie';
console.log(str.startswith('b'));
console.log(str.startswith('a pro'));
console.log(str.endswith('promsie'));
console.log(str.endswith('a'));
}
includes
{
const str = 'a promise is a promise';
if (~str.indexof('promise')) {
console.log('存在"promise"');
}
if (str.includes('a promise')) {
console.log('存在"a promise"');
}
}
字符串转数组+遍历
let str = 'promise';
// 四种方法：转成数组后遍历
var ostr = array.prototype.slice.call(str);
var ostr = str.split('');
const ostr = [...str];
const [...ostr] = str;
console.log(ostr);
//单个字符输出
ostr.foreach(function(word) {
console.log(word);
});
对全是英文的字符串中的大写字符加密 a -> 100 b -> 99
const map = {a: '100', b: '99', c: '98', d: '97', e: '96', f: '95', g: '94', h: '93', i: '92', j: '91', k: '90', l: '89', m: '88', n: '87', o: '86', p: '85', q: '84', r: '83', s: '82', t: '81', u: '80', v: '79',w: '78',x: '77',y: '76', z: '75'};
const words = 'abcdefghijklmnopqrstuvwxyz';
ostr.foreach(function(word, index) {
if (words.includes(word)) ostr[index] = map[word];
});
console.log(ostr.join(''));
使用for-of遍历字符串
let str = 'promise';
let newstr = '';
const map = {a: '100', b: '99', c: '98', d: '97', e: '96', f: '95', g: '94', h: '93', i: '92', j: '91', k: '90', l: '89', m: '88', n: '87', o: '86', p: '85', q: '84', r: '83', s: '82', t: '81', u: '80', v: '79',w: '78',x: '77',y: '76', z: '75'};
for (let word of str) {
if (str.includes(word)) newstr += map[word];
}
console.log(newstr);
unicode是一项标准，包括字符集、编码方案等
解决传统的字符编码方案的局限
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