API

ParamMap: an object with string keys

type ParamMap = Record<string, any>;

For example, { firstParam: 1, 'second-param': 2 } is a valid ParamMap.

urlcat: build full URLs

function urlcat(baseUrl: string, pathTemplate: string, params: ParamMap): string
function urlcat(baseUrl: string, pathTemplate: string): string
function urlcat(baseTemplate: string, params: ParamMap): string

Examples

• urlcat('https://api.example.com', '/users/:id/posts', { id: 123, limit: 10, offset: 120 })
  → 'https://api.example.com/users/123/posts?limit=10&offset=120'
• urlcat('http://example.com/', '/posts/:title', { title: 'Letters & "Special" Characters' })
  → 'http://example.com/posts/Letters%20%26%20%22Special%22%20Characters'
• urlcat('https://api.example.com', '/users')
  → 'https://api.example.com/users'
• urlcat('https://api.example.com/', '/users')
  → 'https://api.example.com/users'
• urlcat('http://example.com/', '/users/:userId/posts/:postId/comments', { userId: 123, postId: 987, authorId: 456, limit: 10, offset: 120 })
  → 'http://example.com/users/123/posts/987/comments?authorId=456&limit=10&offset=120'

NOTE about empty path segments: RFC 3986 allows empty path segments in URLs (for example, https://example.com//users////2). urlcat keeps any empty path segments that aren't at the concatenation boundary between baseUrl and pathTemplate. If you need to include an empty path segment there, you have two options:

• use a double slash: urlcat('https://example.com/', '//users', { q: 1 }) → https://example.com//users?q=1
• use the baseTemplate overload: urlcat('https://example.com//users', { q: 1 }) → https://example.com//users?q=1

query: build query strings

function query(params: ParamMap): string

Builds a query string using the key-value pairs specified. Keys and values are escaped, then joined by the '&' character.

Examples

subst: substitute path parameters

function subst(template: string, params: ParamMap): string

Substitutes parameters with values in a template string. template may contain 0 or more parameter placeholders. Placeholders start with a colon (:), followed by a parameter name that can only contain uppercase or lowercase letters. Any placeholders found in the template are replaced with the value under the corresponding key in params.

Examples

join: join two strings using exactly one separator

function join(part1: string, separator: string, part2: string): string

Joins the two parts using exactly one separator. If a separator is present at the end of part1 or the beginning of part2, it is removed, then the two parts are joined using separator.

Examples