fuse-box/src/analysis/plugins/ImportDeclaration.ts

Fuse-Box a bundler that does it right

import { File } from "../../core/File";

/**
 * Handles require and ImportDeclarations
 * At the moment does not transpile
 */
export class ImportDeclaration {

    /**
     * Extract require statements
     * At the same time replace aliases
     */
    public static onNode(file: File, node: any, parent: any) {
        const analysis = file.analysis;
        if (node.type === "CallExpression" && node.callee) {
            if (node.callee.type === "Identifier" && node.callee.name === "require") {
                let arg1 = node.arguments[0];
                if (analysis.nodeIsString(arg1)) {
                    let requireStatement = this.handleAliasReplacement(file, arg1.value);
                    if (requireStatement) {
                        analysis.registerReplacement(arg1.value, requireStatement);
                        arg1.value = requireStatement;
                        analysis.addDependency(requireStatement);
                    }
                }
            }
        }

        if (node.type === "ExportDefaultDeclaration") {
            file.es6module = true;
        }
        if (node.type === "ExportAllDeclaration") {
            file.es6module = true;
            analysis.addDependency(node.source.value);
        }


        if (node.type === "ImportDeclaration" || node.type === "ExportNamedDeclaration") {
            file.es6module = true;
            if (node.source && analysis.nodeIsString(node.source)) {
                let requireStatement = this.handleAliasReplacement(file, node.source.value);
                node.source.value = requireStatement;
                analysis.addDependency(requireStatement);
            }
        }
    }

    public static onEnd(file: File) {
        if (file.es6module) {
            file.analysis.requiresTranspilation = true
        }
    }

    /**
     * Replace aliases using the context collection
     */
    private static handleAliasReplacement(file: File, requireStatement: string): string {
        // checking for browser override (asa) case
        // these people ...
        // https://github.com/defunctzombie/package-browser-field-spec
        if (file.collection && file.collection.info && file.collection.info.browserOverrides) {
            const overrides = file.collection.info.browserOverrides;
            const pm = file.collection.pm;
            
            if (overrides) {

                if (overrides[requireStatement] !== undefined) {
                    if (typeof overrides[requireStatement] === "string") {
                        requireStatement = overrides[requireStatement];
                        //file.analysis.requiresRegeneration = true;
                    } else {
                        // which means that's is probable "false" and shouldn't be bundled
                        return;
                    }
                } else {
                    const resolved = pm.resolve(requireStatement, file.info.absDir);
                    // it might be solved to a node_module
                    if (resolved && resolved.absPath) {
                        const fuseBoxPath = pm.getFuseBoxPath(resolved.absPath, file.collection.entryFile.info.absDir);
                        if (overrides[fuseBoxPath] !== undefined) {
                            if (typeof overrides[fuseBoxPath] === "string") {
                                requireStatement = overrides[fuseBoxPath];
                                //file.analysis.requiresRegeneration = true;
                            } else {
                                // which means that's is probable "false" and shouldn't be bundled
                                return;
                            }
                        }
                    }
                }

            }
        }

        let result = file.context.replaceAliases(requireStatement)
        if ( result.replaced){
            //file.analysis.requiresRegeneration = true;
        }
        return result.requireStatement;
    }
}