plain-object.md

Plain Object

A plain object

• Inherits directly from Object.prototype or null
• Is not a constructor's prototype property

plain-object/is

Confirms if given object is a plain object

const isPlainObject = require("type/plain-object/is");

isPlainObject({}); // true
isPlainObject(Object.create(null)); // true
isPlainObject([]); // false

plain-object/ensure

If given argument is a plain object it is returned back. Otherwise TypeError is thrown.

const ensurePlainObject = require("type/plain-object/ensure");

ensurePlainObject({}); // {}
ensurePlainObject("foo"); // Thrown TypeError: foo is not a plain object

Confirming on keys

Keys can be validated by passing allowedKeys option. Note that in this case:

• Error message lists up to three invalid keys

const allowedKeys = ["foo"];

ensurePlainObject({}, { allowedKeys }); // {}
ensurePlainObject({ foo: "bar" }, { allowedKeys }); // { foo: 'bar' }

/*
 Below invocation with crash with:
 TypeError: [object Object] is not a valid plain object.
            Following keys are unexpected: lorem, ipsum
*/
ensurePlainObject({ foo: "bar", lorem: 1, ipsum: 2 }, { allowedKeys });

Confirming on property values

Property values can be validated by passing ensurePropertyValue option. Note that in this case:

• A newly created instance of plain object with coerced values is returned
• Error message lists up to three keys that contain invalid values

const ensureString = require("type/string/ensure");

ensurePlainObject({ foo: 12 }, { ensurePropertyValue: ensureString }); // { foo: '12' }

/*
 Below invocation with crash with:
 TypeError: [object Object] is not a valid plain object.
            Valuees for following keys are invalid: lorem, ipsum
*/
ensurePlainObject({ foo: 23, lorem: {}, ipsum: {} }, { ensurePropertyValue: ensureString });