@lukekaalim/to

There and ~~back again~~.

Installation

npm i @lukekaalim/to

Usage

const { toString, toNumber, toObject } = require('@lukekaalim/to');

const toUser = toObject({
  name: toString,
  age: toNumber,
  meta: toObject({
    createdAt: toNumber,
    modifiedAt: toNumber,
  }),
});

const userJson = `
{
  "name": "luke",
  "age": 24,
  "meta": { "createdAt": 0, "modifiedAt": 0 }
}
`;

const user = toUser(JSON.parse(userJson));

Recursive object structure checking for typing those pesky models.

API

toAString

const { toAString } = require('@lukekaalim/to');

const name = toAString('luke'); // name === 'luke'

Identity if the value is a string, throw a NotStringError if not. Naming is seperate than other (Normall would be toString) but is different to avoid naming clashes with the standard object.toString(); method

toNumber

const { toNumber } = require('@lukekaalim/to');

const age = toNumber(25); // age === 25

Identity if the value is a number, throw a NotNumberError if not.

toBoolean

const { toBoolean } = require('@lukekaalim/to');

const isDev = toBoolean(true); // isDev === true

Identity if the value is a boolean, throw a NotBooleanError if not.

toObject

const { toObject } = require('@lukekaalim/to');

const toLukeName = value => {
  if (value === 'luke') {
    return value;
  }
  throw new Error('I\'m not luke!');
};

const toLuke = toObject({
  name: toLukeName,
});

const luke = toLuke({ name: 'luke' });

Given a map of converters, creates a function that accepts an object (Throws a NotObjectError or ValueWasNullError error if not), and creates a new object with properties based on running the arguments through the converter who's key is the property's key. A converted just needs to accept any value, and return anything.

If a converter throws an error, that error is wrapped in a PropertyError.

toArray

const { toArray } = require('@lukekaalim/to');

const toFunc = value => {
  if (typeof value === 'function') {
    return value;
  }
  throw new Error('Not a function!');
};

const toFuncArray = toArray(toFunc);

const funcArray = toFuncArray([console.log, console.error]);

Given a converter, creates a function that accepts an array (Throws a NotArrayError error if not), and creates a new array with elements based on running the converter through each element. A converter just needs to accept any value, and return anything.

If a element throws an error, that error is wrapped in a ElementError.