michaelneu/ts-type-info

Simple TypeScript AST and code generator.

TSTypeInfo

Simple TypeScript AST and code generator.

Uses the TypeScript Compiler API to get information about TypeScript code in an easy to use format.

• Version 6.2 information

npm install ts-type-info --save-dev

AST

// V:\TestFile.ts

export class MyClass {
    myStringProperty: string;
    readonly myNumberProperty = 253;

    myMethod(myParameter: string) {
        return `Test: ${myParameter}`;
    }
}

Get the file info:

import * as TsTypeInfo from "ts-type-info";

const result = TsTypeInfo.getInfoFromFiles(["V:\\TestFile.ts"]);
const property = result.getFile("TestFile.ts")
    .getClass("MyClass")                            // get first by name
    .getProperty(p => p.defaultExpression != null); // or first by what matches

console.log(property.name);                   // myNumberProperty
console.log(property.type.text);              // number
console.log(property.defaultExpression.text); // 253
console.log(property.isReadonly);             // true

// or access the arrays directly
const myMethod = result.files[0].classes[0].methods[0];

console.log(myMethod.name); // myMethod

If you notice a language feature missing please open an issue.

Code Generation

You can work with objects retrieved from the AST or start with your own new file definition:

import * as TsTypeInfo from "ts-type-info";

// create whatever you like at the start
const file = TsTypeInfo.createFile({
    classes: [{
        name: "MyClass",
        methods: [{
            name: "myMethod",
            parameters: [{ name: "myParam", type: "string" }],
            onBeforeWrite: writer => writer.write("// myMethod is here"),
            onWriteFunctionBody: writer => {
                writer.write(`if (myParam != null && myParam.length > 40)`).block(() => {
                    writer.write("alert(myParam)");
                });
                writer.newLine().write("return myParam;");
            }
        }]
    }]
});

// add to it later
const myClass = file.getClass("MyClass");
myClass.isAbstract = true;
myClass.addDecorator({
    name: "MyDecorator"
});

myClass.addProperty({
    name: "myProperty1",
    type: "string"
});
myClass.addProperty({
    name: "myProperty2",
    type: "number",
    defaultExpression: "4"
});

// write it out
console.log(file.write());

Outputs:

@MyDecorator
abstract class MyClass {
    myProperty1: string;
    myProperty2 = 4;

    // myMethod is here
    myMethod(myParam: string) {
        if (myParam != null && myParam.length > 40) {
            alert(myParam);
        }

        return myParam;
    }
}

Simple Examples

• Strict Interfaces - Make all interface properties required and append "Strict" to the end of the interface name.

Full Examples

• Server Bridge - Automatically generates client side code to communicate with the server from the server side code.
• TsObjectCreate - Code generation that writes functions for creating objects with their types.

Include tsNodes

In case there's something you need from the compiler that's not implemented in this library, set the includeTsNodes option to true. This will include the TypeScript compiler nodes in the tsNode property of most objects.

import * as ts from "typescript";
import * as TsTypeInfo from "ts-type-info";

const result = TsTypeInfo.getInfoFromFiles(["V:\\TestFile.ts"], { includeTsNodes: true });
const typeChecker = result.getTypeChecker(); // ts.TypeChecker in case you need it
const myMethod = result.getFile("TestFile.ts").getClass("MyClass").getMethod("myMethod");
const myMethodNode = myMethod.tsNode as ts.MethodDeclaration;

console.log(myMethodNode.body.statements[0].getText()); // "return `Test: ${myParameter}`;"