gis-tools-ts
Version:
A collection of geospatial tools primarily designed for WGS84, Web Mercator, and S2.
74 lines • 2.48 kB
JavaScript
/*! MIT License. Jimmy Wärting <https://jimmy.warting.se/opensource> */
import zlib from 'node:zlib';
// fyi, Byte streams aren't really implemented anywhere yet
// It only exist as a issue: https://github.com/WICG/compression/issues/31
// TRACKER: https://github.com/oven-sh/bun/issues/1723
/**
* @param ctx - the context
* @param handle - the handle
* @returns - the transform
*/
const make = (ctx, handle) => Object.assign(ctx, {
writable: new WritableStream({
/**
* @param chunk - input data
* @returns - `true` if more data can be written
*/
write: (chunk) => {
const canWrite = handle.write(chunk);
if (!canWrite) {
// If the internal buffer is full, wait for 'drain' before continuing.
return new Promise((resolve) => handle.once('drain', resolve));
}
},
/** closes the stream */
close: () => {
handle.end();
},
}),
readable: new ReadableStream({
type: 'bytes',
/**
* @param ctrl - the controller
*/
start(ctrl) {
handle.on('data', (chunk) => ctrl.enqueue(chunk));
handle.once('end', () => ctrl.close());
},
}),
});
globalThis.CompressionStream ??= class CompressionStream {
writable;
readable;
/** @param format - the format to use */
constructor(format) {
if (format === 'br')
make(this, zlib.createBrotliCompress());
else if (format === 'deflate')
make(this, zlib.createDeflate());
else if (format === 'gzip')
make(this, zlib.createGzip());
else if (format === 'deflate-raw')
make(this, zlib.createDeflateRaw());
else
throw new Error(`Unsupported format: ${format}`);
}
};
globalThis.DecompressionStream ??= class DecompressionStream {
writable;
readable;
/** @param format - the format to use */
constructor(format) {
if (format === 'br')
make(this, zlib.createBrotliDecompress());
else if (format === 'deflate')
make(this, zlib.createInflate());
else if (format === 'gzip')
make(this, zlib.createGunzip());
else if (format === 'deflate-raw')
make(this, zlib.createInflateRaw());
else
throw new Error(`Unsupported format: ${format}`);
}
};
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