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

Fuse-Box a bundler that does it right

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

export class LanguageLevel {
    public static onNode(file: File, node: any, parent: any) {
        if (node.async === true) {
            file.setLanguageLevel(ScriptTarget.ES2017);
        } else if (node.kind === "const") {
            file.setLanguageLevel(ScriptTarget.ES2015);
        } else if (node.kind === "let") {
            file.setLanguageLevel(ScriptTarget.ES2015);
        } else if (node.type === "ArrowFunctionExpression") {
            file.setLanguageLevel(ScriptTarget.ES2015);
        }
    }
    public static onEnd(file: File) {
        const target = file.context.languageLevel
        if (file.languageLevel > target) {
            file.analysis.requiresTranspilation = true
        }
    }
}