tiny-schema)

It's like typeof, but it's a function.

``js const is = require('tiny-schema');

is('number')(5); // => true is('number')('hello'); // => false is('string')('hello'); // => true is('boolean')(false); // => true`

But it understands the difference between object and null.

`js is('object')({}); // => true is('object')(null); // => false is('null')(null); // => true is('null')({}); // => false`

And it understands the difference between object and array.

`js is('array')([]); // => true is('array')({}); // => false is('object')([]); // => false`

Inspired by JSON Schema, it can recognize integers.

`js is('integer')(5); // => true is('integer')(5.5); // => false`

And since it knows integers, why not go further?

`js // Positive is('+integer')(-5); // => false is('+integer')(5); // => true is('+integer')(0); // => true

// Negative is('-number')(-5.5); // => true is('-number')(5.5); // => false is('-number')(0); // => true`

And sometimes you might want to exclude those pesky zeros...

`js // Positive is('++integer')(5); // => true is('++integer')(0); // => false

// Negative is('--integer')(-5); // => true is('--integer')(0); // => false`

Validating deep structures could be useful...

`js is('[integer]')([-5, 0, 5]); // => true is('{string}')({ a: 'hello', b: 'world' }); // => true`

Nullable types? Might need those too.

`js is('[string?]?')(['hello']); // => true is('[string?]?')([null]); // => true is('[string?]?')(null); // => true`

Algebraic data types are so in these days.

`js is('number|string')('hello'); // => true is('number|string')(-123); // => true`

Nested algebraic data types within a nullable object? Oh I can validate that in one line of code.

`js is('{integer|boolean}?')({ a: -123, b: true }); // => true is('{integer|boolean}?')(null); // => true`

What if I need to get specific about which strings I accept?

`js is('/^\\w+$/i')('not a word'); // => false is('/^\\w+$/i')('word'); // => true`

What if I need to get specific about which numbers I accept?

`js is('100-200')(150); // => true is('100-200')(200); // => true is('100-200')(201); // => false is('100-200')(150.5); // => false (no fractions in an integer range) is('100.0-200.0')(150.5); // => true (now it accepts fractions)`

Enums are nice. Let's use those.

Can every single feature mentioned thus far be nested and used in every context? Yes? Oh, great.

`js is('true|{boolean|"hello"|[/^\w+$/i?]}|500.2-600.8|[[--integer]?]');`

Jesus, okay I'll stop now.

`$3`

String literals can be created by using "", '', or ` , and each form is practically equivalent. The only difference is that each form's respective quote character must be escaped when referred to literally. Escaping is done by using two quotes in direct succession.

``js is('"The cow said ""moo""."')('The cow said "moo".'); // => true is('The cow said "moo".')('The cow said "moo".'); // => true`

`$3`

Regular expressions are passed directly to the RegExp constructor. To include a literal / character in a regular expression, use two forward slashes in direct succession.

`js is('/^application//json$/i')('application/json'); // => true`

`$3`

When validating a range of numbers, sometimes it's useful to exclude one or both boundaries. This can be done by using the < or > character on the boundary that should be excluded.

`js is('0.0->1.0')(0); // => true is('0.0->1.0')(0.9999); // => true is('0.0->1.0')(1); // => false

is('0.0<-1.0')(0); // => false is('0.0<-1.0')(0.9999); // => true is('0.0<-1.0')(1); // => true

is('0.0<->1.0')(0); // => false is('0.0<->1.0')(0.9999); // => true is('0.0<->1.0')(1); // => false`

> The < and > characters don't correspond to "less than" and "greater than". Rather, they depict an arrow, and should be read as "approaches".

`$3`

The any type can be used to accept any value.

`js is('any')(5); // => true is('any')({}); // => true is('any')(null); // => true`

`$3`

The functions spawned by tiny-schema can be reused without needing to parse the schema string more than once.

`js const isValid = is('{string}');

isValid({ hello: 'world' }); // => true isValid({ hello: 5 }); // => false`

`Limitations`

The purpose of tiny-schema is to provide powerful JSON validation with minimal code use. Because of its terse syntax, typical validations can be done in less than one line of code. However, tiny-schema is not a replacement for JSON Schema.

Unlike JSON Schema, tiny-schema cannot...

- validate each of an object's properties by name - validate that an object has certain property names - validate that an object doesn't have certain property names - validate that an object or array has a minimum or maximum number of properties - use JSON Pointers to implement dependent types

tiny-schema should be seen as an easy-to-use JSON type checker on steroids—not an all-purpose, fully-featured JSON typing system.

`Installation`

`npm install --save tiny-schema``

tiny-schema ![Build Status](https://travis-ci.org/JoshuaWise/tiny-schema)

It's like typeof, but it's a function.

``js const is = require('tiny-schema');

is('number')(5); // => true is('number')('hello'); // => false is('string')('hello'); // => true is('boolean')(false); // => true`

But it understands the difference between object and null.

`js is('object')({}); // => true is('object')(null); // => false is('null')(null); // => true is('null')({}); // => false`

And it understands the difference between object and array.

`js is('array')([]); // => true is('array')({}); // => false is('object')([]); // => false`

Inspired by JSON Schema, it can recognize integers.

`js is('integer')(5); // => true is('integer')(5.5); // => false`

And since it knows integers, why not go further?

`js // Positive is('+integer')(-5); // => false is('+integer')(5); // => true is('+integer')(0); // => true

// Negative is('-number')(-5.5); // => true is('-number')(5.5); // => false is('-number')(0); // => true`

And sometimes you might want to exclude those pesky zeros...

`js // Positive is('++integer')(5); // => true is('++integer')(0); // => false

// Negative is('--integer')(-5); // => true is('--integer')(0); // => false`

Validating deep structures could be useful...

`js is('[integer]')([-5, 0, 5]); // => true is('{string}')({ a: 'hello', b: 'world' }); // => true`

Nullable types? Might need those too.

`js is('[string?]?')(['hello']); // => true is('[string?]?')([null]); // => true is('[string?]?')(null); // => true`

Algebraic data types are so in these days.

`js is('number|string')('hello'); // => true is('number|string')(-123); // => true`

Nested algebraic data types within a nullable object? Oh I can validate that in one line of code.

`js is('{integer|boolean}?')({ a: -123, b: true }); // => true is('{integer|boolean}?')(null); // => true`

What if I need to get specific about which strings I accept?

`js is('/^\\w+$/i')('not a word'); // => false is('/^\\w+$/i')('word'); // => true`

What if I need to get specific about which numbers I accept?

Enums are nice. Let's use those.

Can every single feature mentioned thus far be nested and used in every context? Yes? Oh, great.

`js is('true|{boolean|"hello"|[/^\w+$/i?]}|500.2-600.8|[[--integer]?]');`

Jesus, okay I'll stop now.

`$3`

``js is('"The cow said ""moo""."')('The cow said "moo".'); // => true is('The cow said "moo".')('The cow said "moo".'); // => true`

`$3`

Regular expressions are passed directly to the RegExp constructor. To include a literal / character in a regular expression, use two forward slashes in direct succession.

`js is('/^application//json$/i')('application/json'); // => true`

`$3`

When validating a range of numbers, sometimes it's useful to exclude one or both boundaries. This can be done by using the < or > character on the boundary that should be excluded.

`js is('0.0->1.0')(0); // => true is('0.0->1.0')(0.9999); // => true is('0.0->1.0')(1); // => false

is('0.0<-1.0')(0); // => false is('0.0<-1.0')(0.9999); // => true is('0.0<-1.0')(1); // => true

is('0.0<->1.0')(0); // => false is('0.0<->1.0')(0.9999); // => true is('0.0<->1.0')(1); // => false`

> The < and > characters don't correspond to "less than" and "greater than". Rather, they depict an arrow, and should be read as "approaches".

`$3`

The any type can be used to accept any value.

`js is('any')(5); // => true is('any')({}); // => true is('any')(null); // => true`

`$3`

The functions spawned by tiny-schema can be reused without needing to parse the schema string more than once.

`js const isValid = is('{string}');

isValid({ hello: 'world' }); // => true isValid({ hello: 5 }); // => false`

`Limitations`

Unlike JSON Schema, tiny-schema cannot...

tiny-schema should be seen as an easy-to-use JSON type checker on steroids—not an all-purpose, fully-featured JSON typing system.

`Installation`

`npm install --save tiny-schema``