How to use the @actions/core.getState function in @actions/core

async function run(): Promise {
    try {
        const state = utils.getCacheState();

        // Inputs are re-evaluted before the post action, so we want the original key used for restore
        const primaryKey = core.getState(State.CacheKey);
        if (!primaryKey) {
            core.warning(`Error retrieving key from state.`);
            return;
        }

        if (utils.isExactKeyMatch(primaryKey, state)) {
            core.info(
                `Cache hit occurred on the primary key ${primaryKey}, not saving cache.`
            );
            return;
        }

        let cachePath = utils.resolvePath(
            core.getInput(Inputs.Path, { required: true })
        );
        core.debug(`Cache Path: ${cachePath}`);

export function getCacheState(): ArtifactCacheEntry | undefined {
    const stateData = core.getState(State.CacheResult);
    core.debug(`State: ${stateData}`);
    return (stateData && JSON.parse(stateData)) as ArtifactCacheEntry;
}