目录 DOM处理 数组 方法 总结 DOM处理 DOM 为文档提供了结构化表示，并定义了如何通过脚本来访问文档结构。目的其实就是为了能让js操作html元素而制定的一个规范。DOM就是由节点组成的
目录
- DOM处理
- 数组
- 方法
- 总结
DOM处理
DOM 为文档提供了结构化表示，并定义了如何通过脚本来访问文档结构。目的其实就是为了能让js操作html元素而制定的一个规范。DOM就是由节点组成的。
检查一个元素是否被聚焦
const hasFocus = ele => (ele === document.activeElement);
检查用户是否滚动到页面底部
const isAtBottom = () => document.documentElement.clientHeight + window.scrollY >= document.documentElement.scrollHeight;
获取一个元素的所有兄弟元素
const siblings = ele => [].slice.call(ele.parentNode.children).filter((child) => (child !== ele));
获取元素相对于文档的位置
const getPosition = ele => (r = ele.getBoundingClientRect(), {
left: r.left + window.scrollX, top: r.top + window.scrollY
});
// Example
getPosition(document.body); // { left: 0, top: 0 }
在另一个元素之后插入一个元素
const insertAfter = (ele, anotherEle) => anotherEle.parentNode.insertBefore(ele, anotherEle.nextSibling);
// Or
const insertAfter = (ele, anotherEle) => anotherEle.insertAdjacentElement('afterend', ele);
附：在其他元素之前插入一个元素
const insertBefore = (ele, anotherEle) => anotherEle.parentNode.insertBefore(ele, anotherEle);
// Or
const insertBefore = (ele, anotherEle) => anotherEle.insertAdjacentElement('beforebegin', ele);
在元素后面插入给定的 HTML
const insertHtmlAfter = (html, ele) => ele.insertAdjacentHTML('afterend', html);
附：在元素之前插入给定的 HTML
const insertHtmlBefore = (html, ele) => ele.insertAdjacentHTML('beforebegin', html);
滚动到页面顶部（返回顶部）
const goToTop = () => window.scrollTo(0, 0);
数组
数组判空
// `arr` is an array const isEmpty = arr => !Array.isArray(arr) || arr.length === 0; // Examples isEmpty([]); // true isEmpty([1, 2, 3]); // false
克隆数组
// `arr` is an array const clone = arr => arr.slice(0); // Or const clone = arr => [...arr]; // Or const clone = arr => Array.from(arr); // Or const clone = arr => arr.map(x => x); // Or const clone = arr => JSON.parse(JSON.stringify(arr)); // Or const clone = arr => arr.concat([]);
找到数组中最大值对应的索引
const indexOfMax = arr => arr.reduce((prev, curr, i, a) => curr > a[prev] ? i : prev, 0); // Examples indexOfMax([1, 3, 9, 7, 5]); // 2 indexOfMax([1, 3, 7, 7, 5]); // 2
附：最小值对应的索引
const indexOfMin = arr => arr.reduce((prev, curr, i, a) => curr < a[prev] ? i : prev, 0); // Examples indexOfMin([6, 4, 8, 2, 10]); // 3 indexOfMin([6, 4, 2, 2, 10]); // 2
获取数组的交集
const getIntersection = (a, ...arr) => [...new Set(a)].filter(v => arr.every(b => b.includes(v))); // Examples getIntersection([1, 2, 3], [2, 3, 4, 5]); // [2, 3] getIntersection([1, 2, 3], [2, 3, 4, 5], [1, 3, 5]); // [3]
按键对一组对象进行分组
const groupBy = (arr, key) => arr.reduce((acc, item) => ((acc[item[key]] = [...(acc[item[key]] || []), item]), acc), {});
// Example
groupBy([
{ branch: 'audi', model: 'q8', year: '2019' },
{ branch: 'audi', model: 'rs7', year: '2020' },
{ branch: 'ford', model: 'mustang', year: '2019' },
{ branch: 'ford', model: 'explorer', year: '2020' },
{ branch: 'bmw', model: 'x7', year: '2020' },
], 'branch');
/*
{
audi: [
{ branch: 'audi', model: 'q8', year: '2019' },
{ branch: 'audi', model: 'rs7', year: '2020' }
],
bmw: [
{ branch: 'bmw', model: 'x7', year: '2020' }
],
ford: [
{ branch: 'ford', model: 'mustang', year: '2019' },
{ branch: 'ford', model: 'explorer', year: '2020' }
],
}
*/
删除数组中的重复值
const removeDuplicate = arr => arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i)); // Example removeDuplicate(['h', 'e', 'l', 'l', 'o', 'w', 'o', 'r', 'l', 'd']); // ['h', 'e', 'w', 'r', 'd']
按给定的键对数组中的项进行排序
const sortBy = (arr, k) => arr.concat().sort((a, b) => (a[k] > b[k]) ? 1 : ((a[k] < b[k]) ? -1 : 0));
// Example
const people = [
{ name: 'Foo', age: 42 },
{ name: 'Bar', age: 24 },
{ name: 'Fuzz', age: 36 },
{ name: 'Baz', age: 32 },
];
sortBy(people, 'age');
// returns
// [
// { name: 'Bar', age: 24 },
// { name: 'Baz', age: 32 },
// { name: 'Fuzz', age: 36 },
// { name: 'Foo', age: 42 },
// ]
方法
将 URL 参数转换为对象
const getUrlParams = query => Array.from(new URLSearchParams(query)).reduce((p, [k, v]) => Object.assign({}, p, { [k]: p[k] ? (Array.isArray(p[k]) ? p[k] : [p[k]]).concat(v) : v}), {});
// Examples
getUrlParams(location.search); // Get the parameters of the current URL
getUrlParams('foo=Foo&bar=Bar'); // { foo: "Foo", bar: "Bar" }
// Duplicate key
getUrlParams('foo=Foo&foo=Fuzz&bar=Bar'); // { foo: ["Foo", "Fuzz"], bar: "Bar" }
从 URL 获取参数的值
const getParam = (url, param) => new URLSearchParams(new URL(url).search).get(param);
// Example
getParam('http://domain.com?message=hello', 'message'); // 'hello'
用零作为整数的前缀
const prefixWithZeros = (number, length) => (number / Math.pow(10, length)).toFixed(length).substr(2);
// Or
const prefixWithZeros = (number, length) => `${Array(length).join('0')}${number}`.slice(-length);
// Or
const prefixWithZeros = (number, length) => String(number).padStart(length, '0');
// Example
prefixWithZeros(42, 5); // '00042'
将数字四舍五入到给定的数字位数
const prefixWithZeros = (number, length) => (number / Math.pow(10, length)).toFixed(length).substr(2);
// Or
const prefixWithZeros = (number, length) => `${Array(length).join('0')}${number}`.slice(-length);
// Or
const prefixWithZeros = (number, length) => String(number).padStart(length, '0');
// Example
prefixWithZeros(42, 5); // '00042'
将一个数字截断为给定的小数位数而不进行舍入
const toFixed = (n, fixed) => `${n}`.match(new RegExp(`^-?\\d+(?:\.\\d{0,${fixed}})?`))[0];
// Or
const toFixed = (n, fixed) => ~~(Math.pow(10, fixed) * n) / Math.pow(10, fixed);
// Examples
toFixed(25.198726354, 1); // 25.1
toFixed(25.198726354, 2); // 25.19
toFixed(25.198726354, 3); // 25.198
toFixed(25.198726354, 4); // 25.1987
toFixed(25.198726354, 5); // 25.19872
toFixed(25.198726354, 6); // 25.198726
从对象中移除所有 null 和未定义的属性
const removeNullUndefined = obj => Object.entries(obj).reduce((a, [k, v]) => (v == null ? a : (a[k] = v, a)), {});
// Or
const removeNullUndefined = obj => Object.entries(obj).filter(([_, v]) => v != null).reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {});
// Or
const removeNullUndefined = obj => Object.fromEntries(Object.entries(obj).filter(([_, v]) => v != null));
// Example
removeNullUndefined({
foo: null,
bar: undefined,
fuzz: 42,
});
检查字符串是否为回文
const isPalindrome = str => str === str.split('').reverse().join('');
// Examples
isPalindrome('abc'); // false
isPalindrom('abcba'); // true
将一个字符串转换为 camelCase
const toCamelCase = str => str.trim().replace(/[-_\s]+(.)?/g, (_, c) => c ? c.toUpperCase() : '');
// Examples
toCamelCase('background-color'); // backgroundColor
toCamelCase('-webkit-scrollbar-thumb'); // WebkitScrollbarThumb
toCamelCase('_hello_world'); // HelloWorld
toCamelCase('hello_world'); // helloWorld
将字符串转换为 PascalCase
const toPascalCase = str => (str.match(/[a-zA-Z0-9]+/g) || []).map(w => `${w.charAt(0).toUpperCase()}${w.slice(1)}`).join('');
// Examples
toPascalCase('hello world'); // 'HelloWorld'
toPascalCase('hello.world'); // 'HelloWorld'
toPascalCase('foo_bar-baz'); // FooBarBaz
转义 HTML 特殊字符
const escape = str => str.replace(/&/g, '&').replace(/</g, '<').replace(/>/g, '>').replace(/'/g, ''').replace(/"/g, '"');
// Or
const escape = str => str.replace(/[&<>"']/g, m => ({ '&': '&', '<': '<', '>': '>', '"': '"', "'": ''' })[m]);
将多个空格替换为单个空格
// Replace spaces, tabs and new line characters
const replaceSpaces = str => str.replace(/\s\s+/g, ' ');
// Only replace spaces
const replaceOnlySpaces = str => str.replace(/ +/g, ' ');
// Example
replaceSpaces('this\n is \ta \rmessage'); // 'this is a message'
在字母顺序中对文本文档的行进行排序
const sortLines = str => str.split(/\r?\n/).sort().join('\n');
// Reverse the order
const reverseSortedLines = str => str.split(/\r?\n/).sort().reverse().join('\n');
// Example
sortLines(`Thaddeus Mullen
Kareem Marshall
Ferdinand Valentine
Hasad Lindsay
Mufutau Berg
Knox Tyson
Kasimir Fletcher
Colton Sharp
Adrian Rosales
Theodore Rogers`);
/* Output */
/*
Adrian Rosales
Colton Sharp
Ferdinand Valentine
Hasad Lindsay
Kareem Marshall
Kasimir Fletcher
Knox Tyson
Mufutau Berg
Thaddeus Mullen
Theodore Rogers
*/
将字符串截断为完整的单词（超出隐藏）
const truncate = (str, max, suffix) => str.length < max ? str : `${str.substr(0, str.substr(0, max - suffix.length).lastIndexOf(' '))}${suffix}`;
// Example
truncate('This is a long message', 20, '...'); // 'This is a long...'
取消转义 HTML 特殊字符
const unescape = str => str.replace(/&/g , '&').replace(/</g , '<').replace(/>/g , '>').replace(/�*39;/g , "'").replace(/"/g, '"');
总结
到此这篇关于JS中可能会常用到的一些数据处理方法的文章就介绍到这了,更多相关JS常用数据处理方法内容请搜索自由互联以前的文章或继续浏览下面的相关文章希望大家以后多多支持自由互联！