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
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 asway_nameordirectionvalue: 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.