Typology
Typology is a lightweight data validation library for Node.js and the browser (with or without Browserify).
It can validate variables against native JavaScript types as well as against custom types you can define.
Installation
Install with npm:
// Latest release
npm install typology
// Development version
npm install git+https://github.com/jacomyal/typology.gitUsage
Get the native type of a given variable
var types = require('typology');
types.get(true);
>>> 'boolean'
types.get(/abc/);
>>> 'regexp'
// Native types being:
// 'boolean', 'number', 'string'
// 'function', 'array', 'arguments'
// 'regexp', 'date', 'object'
// 'null', 'undefined', 'primitive'
// 'map', 'set', 'weakmap', 'weakset', 'symbol'Deal with custom types
A custom type can be either be defined by a function returning a boolean or an expressive string or object describing the type you want to check.
Example
// Type defined by a function
var customType = function(variable) {
// Here is an example to know if a variable is an integer:
return typeof variable === 'number' && variable === (variable | 0);
};
// Type defined by an expressive string
var customType = '?string'; // Means you want an optional string
var customType = 'string|number'; // Means you want either a string or a number
// Type defined by a complex object
var customType = {
firstname: 'string',
lastname: 'string',
age: 'number'
};Custom types syntax
| Expression | Description | Examples | Validates |
|---|---|---|---|
'type' |
required | 'string' |
'hello' |
'?type' |
optional | '?string' |
'hello', undefined, null
|
'type1|type2' |
multi-types | 'string|number' |
'hello', 45, 2.34
|
{prop: 'type'} |
complex | {firstname: 'string'} |
{firstname: 'Joachim'} |
['type'] |
lists | ['number'] |
[1, 2, 3] |
'!type' |
exclusive | '!string' |
42 |
Note also that expression can be combined. For instance '?string|number' means an optional string or number variable and '!string|object' means anything but a string or an object.
Overkill example
var myCustomType = {
firstname: 'string',
pseudo: '?string',
account: {
total: '?number|string',
bills: ['number']
}
}Using functions to perform ad-hoc validation
var myCustomType = {
age: 'number',
name: function(v) {
return v === 'Jack' || v === 'John';
}
};Validate a variable against a custom type
var types = require('typology');
types.check(myType, myVariable);
// Example
types.check('number', 1);
>>> true
types.check(
{
firstname: 'string',
lastname: 'string',
age: 'number'
},
{
firstname: 'Joachim',
lastname: 'Murat'
}
);
>>> falseGetting more information about what does not match
var types = require('typology');
types.scan(myType, myVariable);
// Example
types.scan('number', 1);
>>> { expected: 'number',
>>> type: 'number',
>>> value: 1 }
types.scan(
{
firstname: 'string',
lastname: 'string',
age: 'number'
},
{
firstname: 'Joachim',
lastname: 'Murat'
}
);
>>> { error: 'Expected a "number" but found a "undefined".',
>>> expected: 'number',
>>> type: 'undefined',
>>> value: undefined,
>>> path: [ 'age' ] }Create your own typology to add custom types
var Typology = require('typology');
var myTypology = new Typology();
// Then add custom definitions
myTypology.add(myCustomType);
// Example
myTypology.add('User', {
firstname: 'string',
lastname: 'string',
age: '?number'
});
// Then you can use it likewise
myTypology.check('User', {hello: 'world'});
>>> false
// And use it in other types' definition
myTypology.check('User|number', myVar);Checking whether a custom type's definition is valid
var types = require('typology');
types.isValid(customType);
// Example
types.isValid('?string');
>>> true
types.isValid('randomcrap');
>>> falseContribution
Contributions are welcome. Please be sure to add and pass unit tests if relevant before submitting any code.
To setup the project, just install npm dependencies with npm install and run tests with npm test.
Code style
We use prettier for the code style, with its default setup. It is plugged as a precommit hook, so you don't have to worry about it.
Also, as an internal convention, please:
- Write
__myVarfor any global private variable - Write
_myVarfor any instance private variable - Write
myVarany local variable
License
Typology is under a MIT license.