sprintf() lite for JavaScript

Low-fat implementation of the sprintf() function for JavaScript that gets you all you need.

For simple string templates.

{person1} gets easily triggered when {person2} makes fun of CS:GO.

or API endpoint path parameters.

/path/to/{success}/should/not/{be}/hard
/path/to/:success/should/not/:be/hard

Description

string sprintf (string $format [, mixed $args [, mixed $... ]])

Returns a string produced according to the formatting string merged with replacement values.

Compatible specifiers

• d — print an integer as is
• u — print an integer as is
• f — print a float as is
• s — print a string as is

Named keys

• :key - print a value of an object key as is.
• {key} - print a value of an object key as is.

Install

npm install sprintf-lite

Use

ES5

var sprintf = require('sprintf-lite')

ES6

import sprintf from 'sprintf-lite'

Examples IRL

Example #1 Basic anonymous keys replacement

Quick string formatting.

sprintf('%s + %d = %s', 'Two', 3, 'Five')
sprintf('/my/%s/api/%s/number/%d', 'awesome', 'endpoint', 1)

The above example will output:

Two + 3 = Five
/my/awesome/api/endpoint/number/1

Example #2 Basic named keys replacement

Embedding object keys into configuration strings or any string templates.

sprintf('Dear {firstName} {lastName}, ...', {firstName: 'John', lastName: 'Doe'})
sprintf('/users/{userId}/orders/{orderId}', {userId: 654321, orderId: 987654321})
sprintf('/users/:userId/orders/:orderId', {userId: 654321, orderId: 987654321})

The above example will output:

Dear John Doe, ...
/users/654321/orders/987654321
/users/654321/orders/987654321

Example #3 Argument swapping and reuse

Keys can be used multiple times in any arbitrary order.

sprintf('In America, you {do} {what}, in Soviet Russia, {what} {do}s YOU!', {do: 'install', what: 'a package'})

The above example will output:

In America, you install a package, in Soviet Russia, a package installs YOU!