koot/core/webpack/loaders/react-hot.js

Koot.js - React isomorphic framework created by CMUX

// modify based on:
// https://github.com/NoamELB/react-hot-loader-loader

function AddReactHotLoader(source) {

    if (!source || !/^\s*export\s+default/m.exec(source))
        return source

    let newSource = getImportLine() + source

    const className = getExportDefaultClassName(source)
    const classNameExported = getExportDefaultClassNameExported(source)
    const functionName = getExportDefaultFunctionName(source)

    if (className) {
        newSource = transformSourceForClass(newSource, className)
    } else if (classNameExported) {
        newSource = transformSourceForClassExported(newSource, classNameExported)
    } else if (functionName) {
        newSource = transformSourceForNamedFunction(newSource, functionName)
    } else if (checkExportClassDirectly(source)) {
        newSource = transformSourceForExportClassDirectly(newSource)
    } else {
        newSource = transformSourceDefault(newSource)
    }
    // console.log(newSource)
    return newSource
}

// transforms

function transformSourceForClass(source, className) {
    // source = source.replace(/^\s*export\s+default\s+/m, '')
    // source += `\nexport default hot(module)(${className});`
    const regex = new RegExp(`^\\s*export\\s+default\\s+class\\s+${className}\\s+`, 'm')
    source = source.replace(regex, `@hot(module)\nexport default class ${className} `)
    return source
}

function transformSourceForClassExported(source, variableName) {
    const regex = new RegExp(`class(\\s+)${variableName}(\\s+)`, 'm')
    source = source.replace(regex, `@hot(module)\nclass$1${variableName}$1`)
    return source
}

function transformSourceForNamedFunction(source, functionName) {
    source = source.replace(/^\s*export\s+default\s+/m, '')
    source += `\nexport default hot(module)(${functionName});`
    return source
}

function transformSourceDefault(source) {
    source = source.replace(/^\s*export\s+default/m, 'const reactAppToMakeSuperHot =')
    source += `\nexport default hot(module)(reactAppToMakeSuperHot);`
    return source
}

function transformSourceForExportClassDirectly(source) {
    source = source.replace(
        /(^|\r|\n)export\s+default\s+class\s+/,
        `$1@hot(module)\nexport default class `
    )
    return source
}

// getters

function getImportLine() {
    return `import {hot} from 'react-hot-loader';\n`
}

function getExportDefaultClassName(source) {
    let className = ''
    const matches = source.match(/^\s*export\s+default\s+class\s+(.*?)\s+/m)
    if (matches && matches[1] && matches[1] !== 'extends') {
        className = matches[1]
    }
    return className
}

function getExportDefaultFunctionName(source) {
    let functionName = ''
    const matches = source.match(/^\s*export\s+default\s+function\s+([^(\s]*)\s?\(/m)
    if (matches && matches[1]) {
        functionName = matches[1]
    }
    return functionName
}

function getExportDefaultClassNameExported(source) {
    let className = ''
    const matches = source.match(/^\s*export\s+default\s+([^(\s]*)[;]*(\n|$)/m)
    if (matches && matches[1]) {
        className = matches[1]
    }
    if (!className)
        return className

    if ((new RegExp(`class\\s+${className}\\s+`, 'm')).test(source))
        return className

    return ''
}

// checkers

function checkExportClassDirectly(source) {
    return /(^|\r|\n)export\s+default\s+class\s+/.test(source)
}

//

module.exports = AddReactHotLoader