match-json is a light assertion library built with JSON APIs in mind.

JSON API's can only carry JSON types: strings, numbers, booleans, arrays and objects. This library uses that in favor to use functions and regexp to assert JSON API's. You should bring your favorite test library.

npm install match-json

Match JSON Primitives.

// Numbers
match(3.1415, 3.1415); // => true

//Strings
match("Uno Dos Tres", "Uno Dos Tres"); // => true

// Booleans
match(false, false); // => true

// And with undefined and null values
match(undefined, undefined); // => true
match(null, null); // => true

Match Structures (objects and arrays).

match({ name: "Link", color: "green" }, { name: "Link", color: "green" }); // => true
match(["deku", "goron", "zora"], ["deku", "goron", "zora"]); // => true

Matching using Functions

match({ name: "Samus" }, (hero) => hero.name.length >= 5); // => true

Matching using regular expressions

match(
  "fmcloud@nintendo.jp",
  /[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}/
); // => true

Also, match-json can check JSON types using constructor functions

match(5, Number); // => true

match("Hola, mundo", String); // => true

match(false, Boolean); // => true

And everything together!

match(
  {
    name: { first: "Walter", last: "White" },
    age: 51,
    breakingBad: true,
  },
  {
    name: { first: /[\w]*/, last: "White" },
    age: (age) => age > 18,
    breakingBad: Boolean,
  }
); // => true

In an object, the default behavior of partial interpret as an error any extra field received. Partial mode ignores potential extra fields received.

Partial mode is enabled by using the partial function exposed from match-json instead of match-json itself. The rest of functionality is not changed.

NOTE: Only objects (and not arrays) are affected by partial mode.

import match, { partial } from 'match-json';

// No partial mode
match({ id : 5, name: 'john' }, { id: Number }) // => false

// Partial mode
partial({ id : 5, name: 'john' }, { id: Number }) // => true

match-json also provides a bake function that can be used to predefine an expected pattern.

const nameIsLarge = match.bake({ name: (name) => name.length > 10 });
nameIsLarge("Tom"); // => false
nameIsLarge("Tooooooooom"); // => true

• match( a : T, b : T, partialMode : boolean? ) : boolean
• match( a : T, test : RegExp, partialMode : boolean? ) : boolean
• match( a : T, test : PredicateFunction, partialMode : boolean? ) : boolean
• match( a : T, test : JSONTypeConstructorFunction, partialMode : boolean? ) : boolean

• bake( a: T, partialMode : boolean? ) : PredicateFunction

• ( where PredicateFunction = ( w : T ) : boolean )

• ( where JSONTypeConstructorFunction = Number, String OR Boolean )

• Is worth to mention that you only can use JSON-data as the first argument of the function. Not functions or RegExp.
• I made this for test my API endpoints, thats why it only accepts to test JSON data.

Feel free to open an issue and/or make a PR if you found a bug or think in a way this lib or even the README can be improved.

MIT