hustcc / variable-type

👏 ~ 1 kb. Schema validation. 一个只有 1 kb 的用于变量结构校验的库。

variable-type

A high-performance javascript(less then 1 kb) library, runtime type checking for variable and similar objects.

一个非常简单的（仅 1 kb）高性能的用于做变量结构校验的 JavaScript 模块。

Inspired by prop-types.

1. Install

npm i --save variable-type

Then import it.

import VT from 'variable-type';

2. API & Types

Before use it to check variable, you should make your Types.

And the library contains Types below:

• VT.bool
• VT.func
• VT.number
• VT.string
• VT.object
• VT.array
• VT.any
• VT.null
• VT.undefined
• VT.instanceOf(Class)
• VT.typeOf(String)
• VT.in(Array)
• VT.arrayOf(Type)
• VT.shape(TypeObject)
• VT.and(TypeArray)
• VT.or(TypeArray)
• VT.not(Type)
• VT.apply(Function)

The Type has 2 API:

• check(value)
• optional(): convent the type into optional.

You can see all the usage in the test cases file.

If more Types are needed, welcome to send a pull request, or put an issue to me.

3. Usage examples

Here is some examples. More you can see in test.ts file.

• Simple usage

VT.number.check(1992);
VT.string.check('hustcc');
VT.func.check(Math.min);
VT.bool.check(true);
VT.object.check({});
VT.array.check([1, 2, 3]);
VT.null.check(null);
VT.undefined.check(undefined);
VT.instanceOf(Date).check(new Date());
VT.in(['hustcc', 'hust', 'cc']).check('hustcc');

• And / Or / Not

VT.not(VT.in(['hustcc', 'cc'])).check('hustcc');

VT.and([
   VT.string
   VT.in(['hustcc', 1992]),
]).check('hustcc');

VT.or([
   VT.number,
   VT.string,
]).check('hustcc');

• Array type.

const arr = ['hello', 'world', 25, new Date(1992, 8, 1)];
 
const types = VT.arrayOf(
  VT.or([
    VT.number,
    VT.string,
    VT.instanceOf(Date)
  ])
);

types.check(arr); // will get true. 

• Object type.

const obj = {
  name: 'hustcc',
  boy: true,
  birthday: new Date(1992, 8, 1)
};
 
const types = VT.shape({
  name: VT.string,
  boy: VT.bool,
  birthday: VT.instanceOf(Date)
});

types.check(obj); // will get true. 

• Complex example.

// The only API `check`.
VT.shape({
  a: VT.bool,
  b: VT.number,
  c: VT.string,
  d: VT.func,
  e: VT.instanceOf(Date),
  f: VT.in([1, '1']),
  g: VT.shape({
    h: VT.or([
      VT.shape({
        i: VT.arrayOf(
          VT.or([
            VT.number,
            VT.string,
            VT.bool,
            VT.shape({
              j: VT.func
            })
          ])
        )
      })
    ])
  })
}).check({
  a: true,
  b: 1,
  c: 'str',
  d: function() {},
  e: new Date(),
  f: '1',
  g: {
    h: {
      i: [
        '1',
        2,
        true,
        {
          j: function() {}
        }
      ]
    }
  }
}); // Then will get true.

• Optional type

VT.shape({
  name: VT.string,
  birthday: VT.string,
  sex: VT.string.optional()
}).check({
  name: 'hustcc',
  birthday: '1992-08-01'
}); // Then will get true.

4. Test & Perf

# install dependence
$ npm i

# run unit test
$ npm run test

# run performance test
$ npm run perf

[OPS] variable-type / prop-types = 5.033

License

MIT@hustcc.

variable-type's Issues

Skip type checking on production

I believe it's nice to have type checking when working with weak dynamic types, especially with shapes. As far as I know type checking makes sense during developing process or for those people who will read the code in order to have understanding with what types of variables the code works. Languages with type checking will not compile your code until types are correct. So, in runtime it basically makes no sense to check types of variables.
Modern building tools during a building process can read variables from node's environment and replace their value with booleans, e.g.:

// source
if (process.env.NODE_ENV === 'production') {

}

// build (in case if NODE_ENV = production)
if (true) {

}

After that minifiers (like uglifyjs) can exclude such code which is always under false block, because it's never used. This helps to avoid unnecessary calculations on production. React's prop-types does exactly like that.

@hustcc What do you thing about adding the same behavior to variable-type?

Add typescript definition file

Add typescript definition file.