Installing

yarn add test-label

or

npm install --save test-label

About

This is a little function that can be used to convert a labeled statement into a function.

Let's say you want to refactor some overly complex function. It's full of io and too long to split up. What is the easiest way to test this piece of code?

By using test-label

// some-legacy-function.js
module.exports = function foo() {
  var someInternalVariable = 0

  // ... lots of io and weirdness ...

  var bar = someWeirdNestedFunction(163)

  // ... lots of io and weirdness ...

  function someWeirdNestedFunction(maxValue) {

    // The strangeLoop label was added so we
    // have a way to reference the function.
    strangeLoop: for (var i = 0; i < maxValue; i += Math.max(i, 1))
      someInternalVariable += 10
  }
}

// some-legacy-function.spec.js
const labelToFunction = require('test-label')
const legacyFunction = require('./legacy-function.js')
const assert = require('assert')

test('legacy function', () => {
  const fn = labelToFunction(legacyFunction, 'strangeLoop', {
    arguments: ['someInternalVariable', 'maxValue'],
    return: 'someInternalVariable',
  })

  assert.equal(fn(0, 163), 90)
})

Running tests

yarn && yarn test