parse

This function "atomically" parses data (i.e. parses the entire data set in one operation). It can be called on "already loaded" data such as ArrayBuffer and string objects.

In contrast to load, parse does not accept URLs (it treats strings as data to be parsed) however it does read data from Response objects (which can involve loading data from a source). Response objects are returned by fetch but can also be manually created to wrap other data types, which makes parse quite flexible.

caution

When calling parse from a loader to invoke a sub-loader, do not use this function. Use the parseWithContext counterparts in `@loaders.gl/loader-utils``

Usage

The return value from fetch or fetchFile is a Promise that resolves to the fetch Response object and can be passed directly to the non-sync parser functions:

import {fetchFile, parse} from '@loaders.gl/core';
import {OBJLoader} from '@loaders.gl/obj';

data = await parse(fetchFile(url), OBJLoader);
// Application code here
...

Batched (streaming) parsing is supported by some loaders

import {fetchFile, parseInBatches} from '@loaders.gl/core';
import {CSVLoader} from '@loaders.gl/obj';

const batchIterator = await parseInBatches(fetchFile(url), CSVLoader);
for await (const batch of batchIterator) {
  console.log(batch.length);
}

Handling errors

try {
  const response = await fetch(url); // fetch can throw in case of network errors
  const data = await parse(response); // parse will throw if server reports an error
} catch (error) {
  console.log(error);
}

Functions

parse(data: Response | ArrayBuffer | String, loaders: Object | Object[], options?: Object) : Promise<Any>

Parses data asynchronously either using the provided loader or loaders, or using the pre-registered loaders (see register-loaders).

• data: loaded data or an object that allows data to be loaded. This parameter can be any of the following types:

  • Response - response object returned by fetchFile or fetch.
  • ArrayBuffer - Parse from binary data in an array buffer
  • String - Parse from text data in a string. (Only works for loaders that support textual input).
  • Iterator - Iterator that yeilds binary (ArrayBuffer) chunks or string chunks (string chunks only work for loaders that support textual input).
  • AsyncIterator - iterator that yeilds promises that resolve to binary (ArrayBuffer) chunks or string chunks.
  • ReadableStream - A DOM or Node stream.
  • File - A browser file object (from drag-and-drop or file selection operations).
  • Promise - A promise that resolves to any of the other supported data types can also be supplied.

• loaders - can be a single loader or an array of loaders. If single loader is provided, will force to use it. If ommitted, will use the list of pre-registered loaders (see registerLoaders)

• data: loaded data or an object that allows data to be loaded. See table below for valid input types for this parameter.

• loaders - can be a single loader or an array of loaders. If ommitted, will use the list of pre-registered loaders (see registerLoaders)

• options: See LoaderOptions.

• url: optional, assists in the autoselection of a loader if multiple loaders are supplied to loader.

Returns:

• Return value depends on the loader object category

Notes:

• If multiple loaders are provided (or pre-registered), an attempt will be made to autodetect which loader is appropriate for the file (using url extension and header matching).

Data Type	Description	Comments
Response	fetch response object returned by e.g. fetchFile or fetch.	Data will be streamed from the response.body stream.
ArrayBuffer	Parse from binary data in an array buffer
String	Parse from text data in a string.	Only works for loaders that support textual input.
converted into async iterators behind the scenes.
File	A browser file object (from drag-and-drop or file selection operations).
Promise	A promise that resolves to any of the other supported data types can also be supplied.

| Iterator | Iterator that yields binary (ArrayBuffer) chunks or string chunks | string chunks only work for loaders that support textual input. | | AsyncIterator | iterator that yields promises that resolve to binary (ArrayBuffer) chunks or string chunks. |

Note that additional data types can be converted to Response objects and used with parse, e.g. with new Response(new FormData(...)). See browser documentation for the Response class for more details.