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MobxRequestor API Reference

The MobxRequestor class encapsulates your async function and provides reactive (MobX observable/computed) properties and actions.

Constructor​

new MobxRequestor<T, F, K>({
  callFn: F;               // Required. The async function to wrap.
  autoClear?: boolean;      // Default: true. If true, clears the response before each new call.
  defaultResponse?: T;      // Default: null. The initial and fallback value for `.response`.
  transformError?: (error: K) => string; // Optional. Custom error message transformer.
})

Computed Properties​

.response: T | null​

Returns the stored response from the last successful call, falling back to defaultResponse if no response has been stored yet.

.loading: boolean​

true while execCall is in flight, false otherwise.

.success: boolean​

true if the last call resolved successfully.

.initialOrLoading: boolean​

true if the requestor is in its initial state (never called) or currently loading.

.error: string​

Returns the error message from the last failed call.

  • If a transformError function was provided, it is used to produce the string.
  • Otherwise falls back to rawError.type, then rawError.message, then 'UNKNONW_ERROR'.
  • Returns '' (empty string) if there is no error.

.rawError: K | null​

The raw error object from the last failed call, or null.

.uploadComplete: boolean​

true when _uploadProgress reaches 100.

.downloadComplete: boolean​

true when _downloadProgress reaches 100.

Actions (Methods)​

.execCall(...args: Parameters<F>): Promise<void>​

Executes the wrapped async function.

  • Accepts the exact same arguments as the original callFn.
  • Sets .loading to true during execution.
  • On success, sets .response to the resolved value and state to 'success'.
  • On failure, sets .error / .rawError and state to 'error'.
  • If autoClear is true (the default), resets .response to defaultResponse at the start of each call.

.clearError(): void​

Clears the stored error (rawError becomes null, .error becomes '').

.clearResponse(): void​

Resets the response and state back to initial (response becomes defaultResponse, state becomes 'initial').

.clearErrorAndResponse(): void​

Convenience method that calls both .clearError() and .clearResponse().

.setResponse(response: T): void​

Manually sets the response and transitions the state to 'success'.

.setResult(args: SetResultParams<T, K, F>): Promise<void>​

Advanced: manually sets the full result (response, state, error) if the fetchId matches the current call.

.reportUploadProgress({ percentage: number }): void​

Action to update the upload progress percentage.

.reportDownloadProgress({ percentage: number }): void​

Action to update the download progress percentage.

.resetUploadProgress(): void​

Resets upload progress to 0.

.resetDownloadProgress(): void​

Resets download progress to 0.

.resetProgressReport(): void​

Resets both upload and download progress to 0.

Callback​

.onError?: (args: { error: K; fetchId: string; params: Parameters<F> }) => void​

Optional callback invoked when execCall catches an error. Can be assigned after construction.

Exported Types​

export type MobxRequestorState = 'initial' | 'fetching' | 'success' | 'error';

export type MobxRequestorArgs<T, F, K> = {
  callFn: F;
  autoClear?: boolean;
  defaultResponse?: T;
  transformError?: TransformErrorFn<K>;
};

export type SetResultParams<T, K, F> = {
  response: T | null;
  state: MobxRequestorState;
  fetchId: string;
  params: Parameters<F>;
  error?: K | null;
};

export type UploadDownloadProgressArgs = {
  percentage: number;
};