Node

base64

1. btoa（编码）

FROM

30 seconds of code (Node)

FUNCTION：

const btoa = str => Buffer.from(str, 'binary').toString('base64');

EXAMPLES：

btoa('foobar1'); // 'Zm9vYmFyMQ=='

2. atob（解码）

FROM

30 seconds of code (Node)

FUNCTION：

const atob = str => Buffer.from(str, 'base64').toString('binary');

EXAMPLES：

atob('Zm9vYmFyMQ=='); // 'foobar1'1

控制台

1. colorize（色彩）

FROM

30 seconds of code (Node)

DETAIL：

colors 更详细。

FUNCTION：

const colorize = (...args) => ({
  black: `\x1b[30m${args.join(' ')}`,
  red: `\x1b[31m${args.join(' ')}`,
  green: `\x1b[32m${args.join(' ')}`,
  yellow: `\x1b[33m${args.join(' ')}`,
  blue: `\x1b[34m${args.join(' ')}`,
  magenta: `\x1b[35m${args.join(' ')}`,
  cyan: `\x1b[36m${args.join(' ')}`,
  white: `\x1b[37m${args.join(' ')}`,
  bgBlack: `\x1b[40m${args.join(' ')}\x1b[0m`,
  bgRed: `\x1b[41m${args.join(' ')}\x1b[0m`,
  bgGreen: `\x1b[42m${args.join(' ')}\x1b[0m`,
  bgYellow: `\x1b[43m${args.join(' ')}\x1b[0m`,
  bgBlue: `\x1b[44m${args.join(' ')}\x1b[0m`,
  bgMagenta: `\x1b[45m${args.join(' ')}\x1b[0m`,
  bgCyan: `\x1b[46m${args.join(' ')}\x1b[0m`,
  bgWhite: `\x1b[47m${args.join(' ')}\x1b[0m`
});

EXAMPLES：

console.log(colorize('foo').red); // 'foo' (red letters)
console.log(colorize('foo', 'bar').bgBlue); // 'foo bar' (blue background)
console.log(colorize(colorize('foo').yellow, colorize('foo').green).bgWhite); // 'foo bar' (first word in yellow letters, second word in green letters, white background for both)

操作

1. createDirIfNotExists（创建目录）

FROM

30 seconds of code (Node)

FUNCTION：

const fs = require('fs');
const createDirIfNotExists = dir => (!fs.existsSync(dir) ? fs.mkdirSync(dir) : undefined);

EXAMPLES：

createDirIfNotExists('test'); // creates the directory 'test', if it doesn't exist

2. JSONToFile（创建文件）

FROM

30 seconds of code (Node)

FUNCTION：

const fs = require('fs');
const JSONToFile = (obj, filename) =>
  fs.writeFileSync(`${filename}.json`, JSON.stringify(obj, null, 2));

EXAMPLES：

JSONToFile({ test: 'is passed' }, 'testJsonFile'); // writes the object to 'testJsonFile.json'

3. readFileLines（读取文件行）

FROM

30 seconds of code (Node)

FUNCTION：

const fs = require('fs');
const readFileLines = filename =>
  fs
    .readFileSync(filename)
    .toString('UTF8')
    .split('\n');

EXAMPLES：

/*
contents of test.txt :
  line1
  line2
  line3
  ___________________________
*/
let arr = readFileLines('test.txt');
console.log(arr); // ['line1', 'line2', 'line3']

4. untildify（替换波浪号）

FROM

30 seconds of code (Node)

FUNCTION：

const untildify = str => str.replace(/^~($|\/|\\)/, `${require('os').homedir()}$1`);

EXAMPLES：

untildify('~/node'); // '/Users/aUser/node'

crypto

1. hashNode（哈希）

FROM

30 seconds of code (Node)

FUNCTION：

const crypto = require('crypto');
const hashNode = val =>
  new Promise(resolve =>
    setTimeout(
      () =>
        resolve(
          crypto
            .createHash('sha256')
            .update(val)
            .digest('hex')
        ),
      0
    )
  );

EXAMPLES：

hashNode(JSON.stringify({ a: 'a', b: [1, 2, 3, 4], foo: { c: 'bar' } })).then(console.log); // '04aa106279f5977f59f9067fa9712afc4aedc6f5862a8defc34552d8c7206393'

2. UUIDGeneratorNode（UUID）

FROM

30 seconds of code (Node)

FUNCTION：

const crypto = require('crypto');
const UUIDGeneratorNode = () =>
  ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c =>
    (c ^ (crypto.randomBytes(1)[0] & (15 >> (c / 4)))).toString(16)
  );

EXAMPLES：

UUIDGeneratorNode(); // '79c7c136-60ee-40a2-beb2-856f1feabefc'

环境

1. hasFlags

FROM

30 seconds of code (Node)

FUNCTION：

const hasFlags = (...flags) =>
  flags.every(flag => process.argv.includes(/^-{1,2}/.test(flag) ? flag : '--' + flag));

EXAMPLES：

// node myScript.js -s --test --cool=true
hasFlags('-s'); // true
hasFlags('--test', 'cool=true', '-s'); // true
hasFlags('special'); // false

2. isTravisCI

FROM

30 seconds of code (Node)

FUNCTION：

const isTravisCI = () => 'TRAVIS' in process.env && 'CI' in process.env;

EXAMPLES：

isTravisCI(); // true (if code is running on Travis CI)

判断流

1. isDuplexStream

FROM

30 seconds of code (Node)

FUNCTION：

const isDuplexStream = val =>
  val !== null &&
  typeof val === 'object' &&
  typeof val.pipe === 'function' &&
  typeof val._read === 'function' &&
  typeof val._readableState === 'object' &&
  typeof val._write === 'function' &&
  typeof val._writableState === 'object';

EXAMPLES：

const Stream = require('stream');
isDuplexStream(new Stream.Duplex()); // true

2. isReadableStream

FROM

30 seconds of code (Node)

FUNCTION：

const isReadableStream = val =>
  val !== null &&
  typeof val === 'object' &&
  typeof val.pipe === 'function' &&
  typeof val._read === 'function' &&
  typeof val._readableState === 'object';

EXAMPLES：

const fs = require('fs');
isReadableStream(fs.createReadStream('test.txt')); // true

3. isStream

FROM

30 seconds of code (Node)

FUNCTION：

const isStream = val => val !== null && typeof val === 'object' && typeof val.pipe === 'function';

EXAMPLES：

const fs = require('fs');
isStream(fs.createReadStream('test.txt')); // true

4. isWritableStream

FROM

30 seconds of code (Node)

FUNCTION：

const isWritableStream = val =>
  val !== null &&
  typeof val === 'object' &&
  typeof val.pipe === 'function' &&
  typeof val._write === 'function' &&
  typeof val._writableState === 'object';

EXAMPLES：

const fs = require('fs');
isWritableStream(fs.createWriteStream('test.txt')); // true