squiggle/packages/components/src/lib/hooks/useRunnerState.ts
2022-07-27 21:28:21 +04:00

101 lines
2.4 KiB
TypeScript

import { useLayoutEffect, useReducer } from "react";
type State = {
autorunMode: boolean;
renderedCode: string;
// "prepared" is for rendering a spinner; "run" for executing squiggle code; then it gets back to "none" on the next render
runningState: "none" | "prepared" | "run";
executionId: number;
};
const buildInitialState = (code: string): State => ({
autorunMode: true,
renderedCode: "",
runningState: "none",
executionId: 1,
});
type Action =
| {
type: "SET_AUTORUN_MODE";
value: boolean;
code: string;
}
| {
type: "PREPARE_RUN";
}
| {
type: "RUN";
code: string;
}
| {
type: "STOP_RUN";
};
const reducer = (state: State, action: Action): State => {
switch (action.type) {
case "SET_AUTORUN_MODE":
return {
...state,
autorunMode: action.value,
};
case "PREPARE_RUN":
return {
...state,
runningState: "prepared",
};
case "RUN":
return {
...state,
runningState: "run",
renderedCode: action.code,
executionId: state.executionId + 1,
};
case "STOP_RUN":
return {
...state,
runningState: "none",
};
}
};
export const useRunnerState = (code: string) => {
const [state, dispatch] = useReducer(reducer, buildInitialState(code));
useLayoutEffect(() => {
if (state.runningState === "prepared") {
// this is necessary for async playground loading - otherwise it executes the code synchronously on the initial load
// (it's surprising that this is necessary, but empirically it _is_ necessary, both with `useEffect` and `useLayoutEffect`)
setTimeout(() => {
dispatch({ type: "RUN", code });
}, 0);
} else if (state.runningState === "run") {
dispatch({ type: "STOP_RUN" });
}
}, [state.runningState, code]);
const run = () => {
// The rest will be handled by dispatches above on following renders, but we need to update the spinner first.
dispatch({ type: "PREPARE_RUN" });
};
if (
state.autorunMode &&
state.renderedCode !== code &&
state.runningState === "none"
) {
run();
}
return {
run,
autorunMode: state.autorunMode,
renderedCode: state.renderedCode,
isRunning: state.runningState !== "none",
executionId: state.executionId,
setAutorunMode: (newValue: boolean) => {
dispatch({ type: "SET_AUTORUN_MODE", value: newValue, code });
},
};
};