OSRM Text Instructions

OSRM Text Instructions is a Node.js library that transforms route data generated by OSRM into localized turn instructions to be displayed visually or read aloud by a text-to-speech engine. OSRM Text Instructions is the basis of guidance instructions in osrm-frontend, the Mapbox Directions API, and the Mapbox Navigation SDK.

* Global: Text instructions are available in over a dozen languages via Transifex. Abbreviations and advanced grammatical transformations are available in some languages.
* Customizable: Flexible options allow you to format and tweak the results to your liking.
* Cross-platform: A data-driven approach facilitates implementations in other programming languages. OSRM Text Instructions is also available in Swift and Objective-C (for iOS, macOS, tvOS, and watchOS) and in Java (for Android and Java SE).
* Well-tested: A data-driven test suite ensures compatibility across languages and platforms.

Usage


``js
var version = 'v5';
var osrmTextInstructions = require('osrm-text-instructions')(version);

response.legs.forEach(function(leg) {
leg.steps.forEach(function(step) {
instruction = osrmTextInstructions.compile('en', step, options)
});
});
`

If you are unsure if the user's locale is supported by osrm-text-inustrctions, use @mapbox/locale-utils for finding the best fitting language.

#### Parameters require('osrm-text-instructions')(version)

parameter | required? | values | description
---|----|----|---
version | required | v5 | Major OSRM version

#### Parameters compile(language, step, options)

parameter | required? | values | description
---|----|----|---
language | required | en de zh-Hans fr nl ru and more | Compiling instructions for the selected language code.
step | required | OSRM route step object | The RouteStep as it comes out of OSRM
options | optional | Object | See below

##### Options

key | type | description
----|----|----
legCount | integer | Number of legs in the route
legIndex | integer | Zero-based index of the leg containing the step; together with legCount, this option determines which waypoint the user has arrived at
formatToken | function | Function that formats the given token value after grammaticalization and capitalization but before the value is inserted into the instruction string; useful for wrapping tokens in markup
waypointName | string | Optional custom name for the leg's destination, replaces "your {nth} destination"

formatToken takes two parameters:

* token: A string that indicates the kind of token, such as way_name or direction
* value`: A grammatical string for this token, capitalized if the token appears at the beginning of the instruction

and returns a string.

Architecture

* index.js contains the main transformation logic in JavaScript.
* languages/ contains the localization files, including raw format strings, abbreviation files, and grammar rules.
* languages.js loads the localizations and contains some localization-related helper functions.
* test/ contains data-driven integration tests and test fixtures for all supported languages.

Contributing

We welcome feedback, code contributions, and translations! Please see CONTRIBUTING.md for details.