node.js - 如何使用 require ('typescript' ).transform？

Question

const ts = require('typescript');

let template = `
         let hello: string = 'hello,world';
`
ts.transform

如何在上述操作中转换字符串？

Answer 1

您可以使用transpile 函数。这将允许您编译任意字符串:

import * as typescript from 'typescript';  

let template = `
         let hello: string = 'hello,world';
         class test{}
`
let errors : typescript.Diagnostic[] = []
let result = typescript.transpile(template, {}, undefined, errors);

// The result
console.log(result);
// The erorrs
for(let err of errors) console.log(err.messageText);

编辑

上面的解决方案有效，但它只检查语法错误而不检查语义错误。进行模块解析并检查语义错误的版本是:

function transpileWithAllErrors(input: string, compilerOptions?: typescript.CompilerOptions, fileName: string = "dynamic.ts", diagnostics?: typescript.Diagnostic[]): string {
    let result: string;
    let host = typescript.createCompilerHost({});
    let sourceFile = typescript.createSourceFile(fileName, template, typescript.ScriptTarget.ES5);
    let orginalGetSourceFile = host.getSourceFile;
    host.getSourceFile = (file, languageVersion, onError, shouldCreateNewSourceFile) =>
        file == fileName ?
            sourceFile :
            orginalGetSourceFile(file, languageVersion, onError, shouldCreateNewSourceFile);

    host.getCurrentDirectory = () => "";
    host.getDefaultLibLocation = () => "node_modules/typescript/lib";
    host.getDefaultLibFileName = () => "node_modules/typescript/lib/lib.d.ts";

    let program = typescript.createProgram([fileName], {}, host);

    // Capture output, 
    host.writeFile = (wFileName, data) =>{ 
        if(wFileName.endsWith(".js")) {
            result = data;
        }
    };

    if (diagnostics != null) {
        diagnostics.push(...program.getSyntacticDiagnostics(sourceFile));
        diagnostics.push(...program.getSemanticDiagnostics(sourceFile));
        diagnostics.push(...program.getOptionsDiagnostics());
    }
    program.emit(sourceFile);
    return result;
}

用法:

let diagnostics: typescript.Diagnostic[] = []
let result = transpileWithAllErrors(template, {}, undefined, diagnostics);
for (let err of diagnostics) console.log(err.messageText);
console.log(result);

注意:此方法相对于当前路径进行模块解析，因此脚本可以访问安装在当前路径中的任何模块。此外，我没有对代码进行广泛的测试，但它应该可以工作。