[](https://www.npmjs.com/package/mock-build) [](https://nodejs.org/en/) [



Create reusable mocks using the builder pattern in Typescript
```
yarn add mock-build
`typescript
interface UserInfo {
id: number;
userName: string;
email: string;
}
const userInfo = mockBuilder
.id(1)
.userName('foo')
.email('foo@bar.baz')
.build();
`
A note of caution: when building objects from scratch, the builder currently cannot ensure that all
mandatory fields have been set. The built object might thus violate the contract of the given interface.
For example, the following will compile (see also the example in the tests):
`typescript`
const brokenUserInfo = mockBuilder
A way around this is to use template objects (see Usage with template objects).
Another way is to use strictMockBuilder (see Usage with strictMockBuilder).
`typescript
const baseUserInfo = mockBuilder
.id(1)
.userName('foo')
.email('foo@bar.baz');
const userInfo = baseUserInfo.id(2).build();
// {
// id: 2,
// userName: "foo",
// email: "foo@bar.baz"
// }
const otherUserInfo = baseUserInfo.id(3).build();
// {
// id: 3,
// userName: "foo",
// email: "foo@bar.baz"
// }
`
You can also specify a template object, which allows easy creation of variation of objects.
This is especially useful for making test data setup more readable:
`typescript
const defaultUserInfo: UserInfo = {
id: 1,
userName: 'foo',
email: 'foo@bar.baz',
};
const modifiedUserInfo = mockBuilder(defaultUserInfo).id(2).build();
`
Notes:
- With this approach, if the template object conforms to the interface, the
built object will, too.
- The builder will effectively create and modify a shallow copy of the template object.
You can also specify a class object.
`typescript
class UserInfo {
id!: number;
userName!: string;
email!: string;
}
const userInfo = mockBuilder(UserInfo) // note that ( ) is used instead of < > here
.id(1)
.userName('foo')
.email('foo@bar.baz')
.build();
`
Moreover, you can also specify a class object with a template object.
`typescript
class UserInfo {
id!: number;
userName!: string;
email!: string;
}
const userInfo = mockBuilder(UserInfo, {id: 1, userName: 'foo'})
.userName:('foo bar')
.email('foo@bar.baz')
.build();
`
strictMockBuilder is used to make sure all variables are initialized.
`typescript
interface UserInfo {
id: number;
userName: string;
email: string;
}
const userInfo = strictMockBuilder
// Type 'never' has no call signatures.ts(2349)
`
All variables must be initialized before calling build().
`typescript`
const userInfo = strictMockBuilder
.id(1)
.userName('foo')
.email('foo@bar.baz')
.build(); // build() is called successfully
Notes:
strictMockBuilder does not support classes.
1. Fork it!
2. Create your feature branch: git checkout -b my-new-featuregit commit -am 'Add some feature'
3. Commit your changes: git push origin my-new-feature`
4. Push to the branch:
5. Submit a pull request :D
https://github.com/Vincent-Pang/builder-pattern is the original repository that this was forked from.
This project is licensed under the MIT License - see the LICENSE file for details