thebespokepixel/term-ng

/* ────────╮
 │ Term-NG │ Next generation terminal detector
 ╰─────────┴─────────────────────────────────────────────────────────────────── */
/* eslint complexity:0 */

const itermSession = process.env.ITERM_SESSION_ID && process.env.ITERM_SESSION_ID.indexOf(':') > 0
const colorTermTruecolor = process.env.COLORTERM && process.env.COLORTERM.includes('truecolor')
const termColor16m = process.env.TERM_COLOR && process.env.TERM_COLOR.includes('16m')

const has16m = itermSession || colorTermTruecolor || termColor16m

if (has16m && !(/-color/.test(process.argv.join('')))) {
    process.argv.splice(2, 0, '--color=16m')
}

// From https://github.com/sindresorhus/has-flag, under MIT license
const hasFlag = flag => {
    const terminatorPos = process.argv.indexOf('--')
    const prefix = /^-{1,2}/.test(flag) ? '' : '--'
    const pos = process.argv.indexOf(prefix + flag)

    return pos !== -1 && (terminatorPos === -1 ? true : pos < terminatorPos)
}

// From https://github.com/chalk/supports-color, under MIT license
const support = level => {
    if (level === 0) {
        return false
    }

    return {
        level,
        hasBasic: true,
        has256: level >= 2,
        has16m: level >= 3
    }
}

let supportLevel = (() => {
    if (hasFlag('no-color') ||
        hasFlag('no-colors') ||
        hasFlag('color=false')) {
        return 0
    }

    if (hasFlag('color=16m') ||
        hasFlag('color=full') ||
        hasFlag('color=truecolor')) {
        return 3
    }

    if (hasFlag('color=256')) {
        return 2
    }

    if (hasFlag('color') ||
        hasFlag('colors') ||
        hasFlag('color=true') ||
        hasFlag('color=always')) {
        return 1
    }

    if (process.stdout && !process.stdout.isTTY) {
        return 0
    }

    if (process.platform === 'win32') {
        return 1
    }

    if ('CI' in process.env || 'TEAMCITY_VERSION' in process.env) {
        return 0
    }

    if ('COLORTERM' in process.env) {
        return 1
    }

    if (process.env.TERM === 'dumb') {
        return 0
    }

    if (/^xterm-256(?:color)?/.test(process.env.TERM)) {
        return 2
    }

    if (/^screen|^xterm|^vt100|color|ansi|cygwin|linux/i.test(process.env.TERM)) {
        return 1
    }

    return 0
})()

if (supportLevel === 0 && 'FORCE_COLOR' in process.env) {
    supportLevel = 1
}

const supportsColor = process && support(supportLevel)

/**
 * Terminal features.
 * @namespace
 */
const termNG = {
    /**
     * Supported terminal color depth.
     * @type {Object}
     * @property {Number} level  - 0 = None, 1 = Basic, 2 = 256 colors, 3 = 24 bit color
     * @property {Boolean} basic - Is there basic color support?
     * @property {Boolean} has256 - Terminal supports 256 colors
     * @property {Boolean} has16m - Terminal supports 16 million (24 bit) color
     */
    color: {
        level: supportsColor.level || 0,
        basic: supportsColor.hasBasic || false,
        hasBasic: supportsColor.hasBasic || false,
        has256: supportsColor.level >= 2,
        has16m: supportsColor.level >= 3
    },
    /**
     * Does the terminal support inline images?
     * @type {Boolean}
     * @example <caption>To set:</caption>
     * env TERM_IMAGES=enabled
     */
    images: (process.env.TERM_IMAGES !== undefined) && supportsColor.level >= 2,
    /**
     * Does the terminal support audio?
     * @type {Boolean}
     * @example <caption>To set:</caption>
     * env TERM_AUDIO=enabled
     */
    audio: process.env.TERM_AUDIO !== undefined,
    /**
     * Terminal font character set.
     * @type {Object}
     * @property {Boolean} basic    - Font has basic box drawing symbols.
     * @property {Boolean} enhanced - Font has 'full' Unicode character support
     * @example <caption>To set:</caption>
     * env TERM_FONT=[box|full]
     */
    font: {
        basic: process.env.TERM_FONT !== undefined,
        enhanced: process.env.TERM_FONT === 'full'
    },
    /**
     * Termcap support
     * @type {Object}
     * @property {Boolean} basic    - Using the default termcap.
     * @property {Boolean} enhanced - Using an enhanced/custom termcap.
     * @example <caption>To set:</caption>
     * env TERM_ENHANCED=enabled
     */
    termcap: {
        basic: process.env.TERM_ENHANCED !== undefined && process.env.TERM_ENHANCED === 'disabled',
        enhanced: process.env.TERM_ENHANCED === 'enabled'
    },
    /**
     * Name of running terminal software, i.e. 'iTerm.app'
     * @type {String}
     */
    software: process.env.TERM_PROGRAM || process.env.TERMKIT_HOST_APP || process.env.TERM || process.env.GULP
}

export default termNG