As it is known that Typescript is completely opensource now. which is available at Tyescript. I am building an application that will get Typescript code as input and give output the AST of the given code. Provide me a proper way to extract this AST(Abstract Syntax Tree) of input Typescript code rather than comppliling it and converting it into Javascript.
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You could also inspect the AST in a more visual way in astexplorer.netStefan van de Vooren– Stefan van de Vooren2018-11-07 10:14:42 +00:00Commented Nov 7, 2018 at 10:14
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2 Answers
Basic code:
const fileNames = ["C:\\MyFile.ts"];
const compilerOptions: ts.CompilerOptions = {
// compiler options go here if any...
// look at ts.CompilerOptions to see what's available
};
const program = ts.createProgram(fileNames, compilerOptions);
const typeChecker = program.getTypeChecker();
const sourceFiles = program.getSourceFiles();
sourceFiles.filter(f => /MyFile\.ts$/.test(f.fileName)).forEach(sourceFile => {
ts.forEachChild(sourceFile, node => {
const declaration = node as ts.Declaration;
if (declaration.name) {
console.log(declaration.name.getText());
}
});
});
So if you provided that with a C:\MyFile.ts like:
class MyClass {}
interface MyInterface {}
It would output MyClass and MyInterface.
Figuring out everything beyond what I've just shown is a lot of work. It might be more beneficial for you to look at and/or help contribute to this work in progress.
6 Comments
Ahmed Raza
I did not understand the area {/* compiler options go here*/}. Please explain what is its mean?
David Sherret
@AhmedRaza compiler options like what is found in tsconfig.json. The type will be
ts.CompilerOptions. I'll update my answer.Ahmed Raza
Please share any example related to it.
David Sherret
@AhmedRaza I updated it with a working example, but you will have to figure out the rest. It's a lot of work.
Ahmed Raza
yes its good but it is also give the same output if i declare any variable or function in class and interface. How can i extract the variables and functions in class.
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TypeScript compiler doesn't support it but you can do it using recast and babylon@next. Although you will have to trust in the syntax defined by these technologies for representing TypeScript code AST and that they will keep up to date - since TypeScript has new language features release by release (short period of time) - is not like other languages (JavaScript) where you have well defined versions and released in a standard - so if your users start using new language features these technologies (mostly babylon) should keep up to date:
// npm install recast babylon@next
const source = `
interface I {
color: string
}
class C implements I{
color: string='blue'
}
`
const recast = require('recast')
const tsParser = require("recast/parsers/typescript")
const ast = recast.parse(source, {
parser: tsParser
});
console.log(`
CODE:
${source}
AST:
${JSON.stringify(ast)}
`);
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