chalk命令行工具，具有轻量级，高性能，学习成本低等特点，适合优化命令行交互。
API非常简单，支持链式调用：chalk.<style>[.<style>…](string, [string…])。参数是个字符串数组。调用链顺序无所谓，但为了避免冲突，放在最后的优先级最高，所以chalk.red.yellow.green等价于chalk.green
const chalk = require('chalk');
const log = console.log;
log(chalk.blue('Hello') + ' World' + chalk.red('!')); // 设颜色
log(chalk.blue.bgRed.bold('Hello world!')); // 也可以设背景色，加粗
log(chalk.blue('Hello', 'World!', 'Foo', 'bar', 'biz', 'baz')); // 参数支持字符串数组
log(chalk.red('Hello', chalk.underline.bgBlue('world') + '!')); // 支持嵌套使用，下划线
// ES6写法
log(`
CPU: ${chalk.red('90%')}
RAM: ${chalk.green('40%')}
DISK: ${chalk.yellow('70%')}
`);
// ES6写法
log(chalk`
CPU: {red 90%}
RAM: {green 40%}
DISK: {rgb(255,131,0) 70%}
`);
log(chalk.keyword('orange')('Yay for orange colored text!')); // 指定颜色名
log(chalk.rgb(123, 45, 67).underline('Underlined reddish color')); // 自定义颜色
log(chalk.hex('#DEADED').bold('Bold gray!')); // 自定义颜色
也可以自定义你的主题：
const chalk = require('chalk');
const error = chalk.bold.red;
const warning = chalk.keyword('orange');
console.log(error('Error!'));
console.log(warning('Warning!'));
支持的颜色 Colors：
black red green yellow blue magenta cyan white gray redBright greenBright yellowBright blueBright magentaBright cyanBright whiteBright
支持的背景色 Background colors：
bgBlack bgRed bgGreen bgYellow bgBlue bgMagenta bgCyan bgWhite bgBlackBright bgRedBright bgGreenBright bgYellowBright bgBlueBright bgMagentaBright bgCyanBright bgWhiteBright
支持的字体方法：
reset - Resets the current color chain. bold - Make text bold. dim - Emitting only a small amount of light. italic - Make text italic. (Not widely supported) underline - Make text underline. (Not widely supported) inverse- Inverse background and foreground colors. hidden - Prints the text, but makes it invisible. strikethrough - Puts a horizontal line through the center of the text. (Not widely supported) visible- Prints the text only when Chalk is enabled. Can be useful for things that are purely cosmetic.
可以用chalk.enabled关闭粉笔：
const ctx = new chalk.constructor({enabled: false});
可以用chalk.level设置粉笔的属性：
const ctx = new chalk.constructor({level: 0});
// level 值如下：
// 0：All colors disabled
// 1：Basic color support (16 colors)
// 2：256 color support
// 3：Truecolor support (16 million colors)