mirror of
https://github.com/jbranchaud/til
synced 2026-01-03 15:18:01 +00:00
38 lines
918 B
Markdown
38 lines
918 B
Markdown
# Start A Machine In A Specific State
|
|
|
|
For testing (or debugging) purposes, it can be handy to get an XState machine
|
|
running from a specific state.
|
|
|
|
Let's say a machine has an initial state of `green` and the other states it can
|
|
be in are `yellow` and `red`. And `yellow` has sub-states of `walk` and
|
|
`hurry`.
|
|
|
|
By default, a machine will start in the specified initial state.
|
|
|
|
```javascript
|
|
const service = interpret(trafficLightMachine);
|
|
|
|
service.start();
|
|
|
|
service.state.value; //=> 'green'
|
|
```
|
|
|
|
We can tell the traffic light service to start in the `red` state instead.
|
|
|
|
```javascript
|
|
service.start('red');
|
|
|
|
service.state.value; //=> 'red'
|
|
```
|
|
|
|
We can even tell it to start in a sub-state (nested state) of a particular
|
|
state.
|
|
|
|
```javascript
|
|
service.start({ yellow: 'hurry' });
|
|
|
|
service.state.value; //=> { yellow: 'hurry' }
|
|
```
|
|
|
|
[source](https://xstate.js.org/docs/guides/interpretation.html#starting-and-stopping)
|