hein
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1.4.2 • Public • Published

Hein

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Assertion library with focus on TypeScript

Features

Plugins

npm/hein-plugin-sinon - Provides assertions like to.have.been.calledOnce() and to.have.been.calledWith() for sinon spies.

Usage

Assert

import { assert } from 'hein';
import { equal } from 'hein/assert';

equal(1, 1);
assert.equal(1, 1);

Expect

import { expect } from 'hein';
expect(1).to.equal(1);

Chainable properties

  • a
  • an
  • and - used to chain multiple assertions, clears the state (so .not will be reset)
  • be
  • have
  • not - inverts the expectation (ie expect(5).to.not.equal(5) will throw)
  • to

Assertions

above

Alias for greaterThan

array

Assert that value is an array

expect([]).to.be.an.array();
atLeast

Alias for greaterThanOrEqual

atMost

Alias for lessThanOrEqual

ballpark

Assert that value is within a range of expectation (default is 0.1 - within 10%)

expect(1.1).to.be.in.ballpark(1);
expect(120).to.be.in.ballpark(100, 0.2);
below

Alias for lessThan

bigint

Assert that value is a BigInt

expect(BigInt(5)).to.be.a.bigint();
boolean

Assert that value is a boolean

expect(true).to.be.a.boolean();
contain

Alias for include

Date

Assert that value is an instance of Date

expect(new Date()).to.be.a.date();
empty

Assert that array / object / Map / Set is empty

expect([]).to.be.empty();
expect({}).to.be.empty();
expect(new Map()).to.be.empty();
expect(new Set()).to.be.empty();
endWith

Assert that string ends with argument

expect('hein').to.endWith('in');
eql

Assert that value deep equals the expectation. When combined with .partially expected may have missing properties

expect({ a: 1 }).to.eql({ a: 1 });
expect({ a: 1, b: new Date() }).to.partially.eql({ a: 1 });

import { any, createEvaluation } from 'hein';
expect({ a: 1, b: new Date(), c: Math.random() }).to.eql({
    a: 1,
    b: any,
    c: createEvaluation((n) => typeof n === 'number')
});
eq

Alias for equal

equal

Assert that value strictly equals expectation. NaN is treated as a non-unique value. Chaining with .deep is an alias for [#eql]

expect('hein').to.equal('hein');
expect(NaN).to.equal(NaN);
expect({ a: 1 }).to.deep.equal({ a: 1 });
false

Assert that value is false

expect(false).to.be.false();
function

Assert that value is a function

expect(() => {}).to.be.a.function();
greaterThan

Assert that value is greater than expectation

expect(5).to.be.greaterThan(4);
gt

Alias for greaterThan

greaterThanOrEqual

Assert that value is greater than or equal to argument

expect(5).to.be.greaterThanOrEqual(5);
expect(5).to.be.greaterThanOrEqual(4);
gte

Alias for greaterThanOrEqual

include

Assert that element / substring is present in array / string

expect([1, 2, 3]).to.include(2);
expect('hein').to.include('ei');
instanceOf

Assert that value is an instance of provided constructor

expect(new Error()).to.be.an.instanceOf(Error);

keys

Assert that object has keys

expect({ a: 1, b: 2 }).to.have.keys(['a', 'b']);
expect({ a: 1, b: 2 }).to.have.keys('a');
lengthOf

Assert that value has a length equal to argument

expect([1]).to.have.a.lengthOf(1);
expect({ a: 1 }).to.have.a.lengthOf(1);
expect(new Map([['a', 1]])).to.have.a.lengthOf(1);
expect(new Set([1])).to.have.a.lengthOf(1);
expect('hein').to.have.a.lengthOf(4);
isAfter

Assert that date is before argument

expect(new Date(2020, 1, 2)).to.be.after(new Date(2020, 1, 1));
isBefore

Assert that date is before argument

expect(new Date(2020, 1, 1)).to.be.before(new Date(2020, 1, 2));
isBetween

Assert that date or number is between arguments

expect(new Date(2020, 1, 2)).to.be.between(new Date(2020, 1, 1), new Date(2020, 1, 3));
expect(2).to.be.between(1, 3);
lessThan

Assert that value is less than expectation

expect(5).to.be.lessThan(6);
lt

Alias for lessThan

lessThanOrEqual

Assert that value is less than or equal to expectation

expect(5).to.be.lessThanOrEqual(5);
expect(4).to.be.lessThanOrEqual(5);
lte

Alias for lessThanOrEqual

Map

Assert that value is an instance of Map

expect(new Map()).to.be.a.Map();
members

Assert that array contains members of expectation

expect([1, 2, 3]).to.have.members([1, 2]);
// check that the arrays have same length
expect([1, 2, 3]).to.have.same.members([1, 2, 3]);
// check that the members are found in the same order
expect([1, 2, 3]).to.have.ordered.members([1, 2, 3]);
// check for deep equality of members
expect([{ a: 1 }, { b: 2 }]).to.have.deep.members([{ a: 1 }]);
// check for members by partial equality
expect([{ a: 1 }, { b: 2 }]).to.have.partially.members([{ a: 1 }]);
NaN

Assert that value is NaN

expect(NaN).to.be.NaN();
null

Assert that value is null

expect(null).to.be.null();
number

Assert that value is a number

expect(5).to.be.a.number();
object

Assert that value is an object. Null and instances of Array don't count

expect({}).to.be.an.object();
property

Assert that actual has property. Optionally check that propery has value

expect({ a: 1 }).to.have.property('a');
expect({ a: 1 }).to.have.property('a', 1);
reject

Assert that provided Promise rejects. At the moment this is the only assertion that can't be chained, returns a promise

await expect(Promise.reject()).to.reject();
roundTo

Assert that number can be rounded to target

expect(5.5).to.be.roundTo(6);
expect(5.14).to.roundTo(5.1, 1);
expect(110).to.roundTo(100, -2);
Set

Assert that value is an instance of Set

expect(new Set()).to.be.a.Set();
sizeOf

Alias of lengthOf

startWith

Assert that string starts with argument

expect('hein').to.startWith('he');
string

Assert that value is a string

expect('hein').to.be.a.string();
symbol

Assert that value is a symbol

expect(Symbol()).to.be.a.symbol();
throw

Assert that provided function throws

expect(() => {
    throw new Error();
}).to.throw();
true

Assert that value is true

expect(true).to.be.true;
undefined

Assert that value is undefined

expect(undefined).to.be.undefined();
WeakMap

Assert that value is an instance of WeakMap

expect(new WeakMap()).to.be.a.WeakMap();
WeakSet

Assert that value is an instance of WeakSet

expect(new WeakSet()).to.be.a.WeakSet();

Modifiers

excluding

Exclude properties from assertion

expect({ a: 1, b: 2 }).excluding('a').to.eql({ b: 2 });

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Install

npm i hein

Homepage

heinjs.com/

Weekly Downloads

131

Version

1.4.2

License

MIT

Unpacked Size

232 kB

Total Files

282

Last publish

Collaborators

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