Lit Snipper

A small tool to snip and format sections of code for markdown-based literature.

Usage

Let's say we have a file called my-example.lit.ts with this content:

import * as cdk from '@aws-cdk/core';
import { IntrinsicValidator, Validation } from '..';
import { TestLambdas } from './test-lambdas';

/** @internal */
export class ItLitLambda extends cdk.Stack {
  constructor(scope_: cdk.Construct, props: cdk.StackProps = {}) {
    super(scope_, 'ItLitLambda', props);

    const testLambdas = new TestLambdas(this, 'TestLambdas');
    const lambdaFunction = testLambdas.alwaysSucceeds;

    // Lit code uses 'scope'
    const scope = this;

    // ::SNIP
    new IntrinsicValidator(scope, 'IntrinsicValidator', {
      validations: [
        Validation.lambdaInvokeSucceeds({
          lambdaFunction,
        }),
      ],
    });
    // ::END-SNIP
  }
}

When you run the lit-snip like this:

npx -p @wheatstalk/lit-snip lit-snip ./my-example.lit.ts

The script will output all the lines between ::SNIP and ::END-SNIP and it will adjust the indentation to match the ::SNIP line's comment, wrapping the example in a markdown code block like this:

new IntrinsicValidator(scope, 'IntrinsicValidator', {
  validations: [
    Validation.lambdaInvokeSucceeds({
      lambdaFunction,
    }),
  ],
});

You might find this useful in conjunction with markmac to keep your README.md code examples in sync with tests that prove the examples work.