BuilderOverOptionsBag [pattern] v1.0.0

When a constructor or factory function takes more than 3–4 parameters, replace the options-bag with a fluent builder. A builder surfaces required vs optional configuration, is self-documenting at the call site, and is easy to extend without breaking callers.

Label

Builder pattern over large options-bag constructor

Problem

    // An options bag with 6 properties — which are required? what are the defaults?
    new HttpClient({
      baseURL: 'https://api.example.com',
      timeout: 5000,
      retries: 3,
      headers: { Authorization: `Bearer ${token}` },
      validateStatus: (s) => s < 500,
      debug: false,
    });
  

Solution

    // Builder: steps are named, required fields enforced by type state
    const client = HttpClient
      .create('https://api.example.com')   // required: baseURL
      .withTimeout(5000)
      .withRetries(3)
      .withHeader('Authorization', `Bearer ${token}`)
      .build();                            // returns immutable HttpClient
  

BuilderOverOptionsBag [pattern] v1.0.0

When a constructor or factory function takes more than 3–4 parameters, replace the options-bag with a fluent builder. A builder surfaces required vs optional configuration, is self-documenting at the call site, and is easy to extend without breaking callers.

Label

Builder pattern over large options-bag constructor

Problem

    // An options bag with 6 properties — which are required? what are the defaults?
    new HttpClient({
      baseURL: 'https://api.example.com',
      timeout: 5000,
      retries: 3,
      headers: { Authorization: `Bearer ${token}` },
      validateStatus: (s) => s < 500,
      debug: false,
    });
  

Solution

    // Builder: steps are named, required fields enforced by type state
    const client = HttpClient
      .create('https://api.example.com')   // required: baseURL
      .withTimeout(5000)
      .withRetries(3)
      .withHeader('Authorization', `Bearer ${token}`)
      .build();                            // returns immutable HttpClient
  

Relations

related: [@team/pattern-named-arguments, @team/rule-no-magic-numbers, @team/principle-readability-over-cleverness] see-also: [@team/pattern-named-arguments]

Label

Builder pattern over large options-bag constructor

Problem

    // An options bag with 6 properties — which are required? what are the defaults?
    new HttpClient({
      baseURL: 'https://api.example.com',
      timeout: 5000,
      retries: 3,
      headers: { Authorization: `Bearer ${token}` },
      validateStatus: (s) => s < 500,
      debug: false,
    });
  

Solution

    // Builder: steps are named, required fields enforced by type state
    const client = HttpClient
      .create('https://api.example.com')   // required: baseURL
      .withTimeout(5000)
      .withRetries(3)
      .withHeader('Authorization', `Bearer ${token}`)
      .build();                            // returns immutable HttpClient
  

See Also

• @team/pattern-named-arguments