gramjs/gramjs_generator/generators/errors.js

const generateErrors = (errors, f) => {
    // Exact/regex match to create {CODE: ErrorClassName}
    const exactMatch = []
    const regexMatch = []

    // Find out what subclasses to import and which to create
    const importBase = new Set()
    const createBase = {}

    for (const error of errors) {
        if (error.subclassExists) {
            importBase.add(error.subclass)
        } else {
            createBase[error.subclass] = error.intCode
        }

        if (error.hasCaptures) {
            regexMatch.push(error)
        } else {
            exactMatch.push(error)
        }
    }

    // Imports and new subclass creation
    f.write(`const { RPCError, ${[...importBase.values()].join(', ')} } = require('./rpcbaseerrors');`)

    f.write('\nconst format = require(\'string-format\');')

    for (const [cls, intCode] of Object.entries(createBase)) {
        f.write(`\n\nclass ${cls} extends RPCError {\n    constructor() {\n        this.code = ${intCode};\n    }\n}`)
    }

    // Error classes generation
    for (const error of errors) {
        f.write(`\n\nclass ${error.name} extends ${error.subclass} {\n    constructor(args) {\n        `)

        if (error.hasCaptures) {
            f.write(`const ${error.captureName} = Number(args.capture || 0);\n        `)
        }

        const capture = error.description.replace(/'/g, '\\\'')

        if (error.hasCaptures) {
            f.write(`super(format('${capture}', {${error.captureName}})`)
        } else {
            f.write(`super('${capture}'`)
        }

        f.write(' + RPCError._fmtRequest(args.request));\n')

        if (error.hasCaptures) {
            f.write(`        this.${error.captureName} = ${error.captureName};\n`)
        }

        f.write('    }\n}\n')
    }

    f.write('\n\nconst rpcErrorsObject = {\n')

    for (const error of exactMatch) {
        f.write(`    ${error.pattern}: ${error.name},\n`)
    }

    f.write('};\n\nconst rpcErrorRe = [\n')

    for (const error of regexMatch) {
        f.write(`    [/${error.pattern}/, ${error.name}],\n`)
    }

    f.write('];')
    f.write('module.exports = {')
    for (const error of regexMatch) {
        f.write(`     ${error.name},\n`)
    }
    for (const error of exactMatch) {
        f.write(`     ${error.name},\n`)
    }
    f.write('     rpcErrorsObject,\n')
    f.write('     rpcErrorRe,\n')

    f.write('}')
}

module.exports = {
    generateErrors,
}