README.md

TypeAssert

Yet another type assertion library.

Importing

Till now this stuff is published nowhere. Just copy the released .js (if you use ESM) or .cjs (if you use CJS) file to your project would be fine.

Basic usages & Advantages

• Assert your object's type with typeAssert

const { typeAssert } = require('./typeAssert')

typeAssert(1, 'number')
typeAssert('2', 'string')

• Build complex assertions intuitively

typeAssert({
  x: 1,
  y: '2',
  z: [3, 4, 5],
  t: { a: [ '6', null ] }
}, {
  x: 'number',
  y: 'string',
  z: ['number'],
  t: {
    a: [ 'string?' ]
  }
})

• Easily extend the functionalities

typeAssert(5, 'number'.assertValue(5))
typeAssert([1, 2, 3], ['number'].chainWith(x => x.length >= 2))

• Intuitive error messages

typeAssert({
    x: 1,
    y: '2',
    z: [3, 4, 5],
    t: { a: [ '5', '6', null, 7, '8' ] } // here is a number 7
}, {
    x: 'number',
    y: 'string',
    z: ['number'],
    t: {
        a: [ 'string?' ]
    }
})

// error message:
//   Trace: Type assertion failed: "object.t.a[3]": expected type "string", got "number"

For more examples, check out test.cjs. That's all, thanks

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