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clean-architecture-frontend…/src/application/view-models/async-state.js
T

82 lines
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JavaScript

export const ASYNC_BASE_STATES = Object.freeze([
"initial-loading",
"success",
"empty",
"terminal-error",
]);
export const ASYNC_OVERLAYS = Object.freeze([
"refreshing",
"stale-degraded",
"mutation-pending",
"mutation-conflict",
]);
/**
* @typedef {{
* data?: unknown,
* isInitialLoading?: boolean,
* failure?: import("../../contracts/errors.js").ApiFailure,
* isFetching?: boolean,
* isStale?: boolean,
* isDegraded?: boolean,
* isMutationPending?: boolean,
* hasMutationConflict?: boolean
* }} AsyncSignals
*/
/** @param {AsyncSignals} signals */
export function deriveAsyncState(signals) {
const hasData = signals.data !== undefined && signals.data !== null;
const empty =
hasData &&
((Array.isArray(signals.data) && signals.data.length === 0) ||
signals.data === "");
let base;
if (signals.isInitialLoading && !hasData) {
base = "initial-loading";
} else if (signals.failure && !hasData) {
base = "terminal-error";
} else if (empty) {
base = "empty";
} else if (hasData) {
base = "success";
} else {
base = "initial-loading";
}
const overlay = Object.freeze({
refreshing: Boolean(signals.isFetching && hasData),
staleDegraded: Boolean(signals.isStale && signals.isDegraded && hasData),
mutationPending: Boolean(signals.isMutationPending && hasData),
mutationConflict: Boolean(signals.hasMutationConflict && hasData),
});
const state = {
base,
data: base === "success" || base === "empty" ? signals.data : undefined,
failure: base === "terminal-error" ? signals.failure : undefined,
overlay,
indicator: selectOverlayIndicator(overlay),
};
return Object.freeze(state);
}
/**
* @param {{
* refreshing: boolean,
* staleDegraded: boolean,
* mutationPending: boolean,
* mutationConflict: boolean
* }} overlay
*/
export function selectOverlayIndicator(overlay) {
if (overlay.mutationConflict) return "mutation-conflict";
if (overlay.mutationPending) return "mutation-pending";
if (overlay.staleDegraded) return "stale-degraded";
if (overlay.refreshing) return "refreshing";
return null;
}