@tmurphree/validation-error-messages v1.0.4

validation-error-messages

Companion library to @tmurphree/validation-predicates.

Why

Makes it easier for you to make complicated validation messages.

Change log

Link

Installation

npm install --save @tmurphree/validation-error-messages

Usage

const { isObjectLike } = require('@tmurphree/validation-predicates');

const { makeIsObjectLikeMessage } = require('@tmurphree/validation-error-messages');

const template = { password: '***', userName: 'something' };

// the long way
if (!(isObjectLike(input, template))) {
  throw new Error('Yikes!  input is not valid but I have no idea why!  Now I have to run complicated code to find it.');
}

// uses this library and makes good error messages quickly
// throws Error('input is missing at least one property: password.')
if (!(isObjectLike(input, template))) {
  throw new Error(makeIsObjectLikeMessage(input, template));
}

Strict mode

Important
The options settings in @tmurphree/validation-predicates and @tmurphree/validation-error-messages MUST be the same for things to act as expected. This includes but is not limited to strict mode (because strict mode is just a quick way to set options).

Strict mode options in this library mirror the strict mode options in @tmurphree/validation-predicates.

Without strict mode:

const { makeIsObjectLikeMessage } = require('@tmurphree/validation-error-messages');

With strict mode:

const { makeIsObjectLikeMessage } = require('@tmurphree/validation-error-messages').strict;

Functions

makeExpectedPropsMessage

/**
 * @description Make an error message for isObjectWithExpectedProps.
 * @param {object} x The object to test.
 * @param {string[]} expectedProperties The required properties.
 * @param {string} [variableName='input'] The name you want printed in the message.
 * @returns {string|undefined} string|undefined
*/
makeExpectedPropsMessage(input, expectedProperties, [variableName]);

Sample output:

• input is not an object.
• input is missing at least property foo.
• undefined (returns undefined if for some reason all of the expected properties are there)

makeIsObjectLikeMessage

  /**
   * @description Make an error message for isObjectLike.
   * @param {object} x The object to test.
   * @param {object} template The object you want x to look like.
   * @param {string} [variableName='input'] The name you want printed in the message.
   * @param {object} [options]
   * @param {boolean} [options.allowExtraProps=false] Return undefined if the object to test has
   *   properties not in template and other tests pass.
   * @param {boolean} [options.checkType=false]  If true check property data types.
   * @returns {string|undefined} string|undefined
  */
makeIsObjectLikeMessage(x, template, [variableName], [options]);

Sample output:

• input is not an object.
• input is missing at least property foo.
• input has at least one additional property someSuperCoolProperty.
• input.fizz is type string and expected type boolean.
• undefined (returns undefined if for some reason all of the expected properties are there and, if checkType is true, they're of the expected type)