39 lines
1.5 KiB
TypeScript
39 lines
1.5 KiB
TypeScript
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#!/usr/bin/env -S deno run --allow-net
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// @deno-types="https://cdn.sheetjs.com/xlsx-latest/package/types/index.d.ts"
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import { read, stream, Sheet2CSVOpts, WorkSheet } from 'https://cdn.sheetjs.com/xlsx-latest/package/xlsx.mjs';
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interface Resumable { resume:()=>void; };
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/* Generate row strings from a worksheet */
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function sheet_to_csv_cb(ws: WorkSheet, cb:(d:string|null)=>void, opts: Sheet2CSVOpts = {}, batch = 1000): Resumable {
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stream.set_readable(() => ({
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__done: false,
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// this function will be assigned by the SheetJS stream methods
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_read: function() { this.__done = true; },
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// this function is called by the stream methods
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push: function(d: string|null) {
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if(!this.__done) cb(d);
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if(d == null) this.__done = true;
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},
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resume: function pump() {
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for(var i = 0; i < batch && !this.__done; ++i) this._read();
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if(!this.__done) setTimeout(pump.bind(this), 0);
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}
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}));
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return stream.to_csv(ws, opts) as Resumable;
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}
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/* Callback invoked on each row (string) and at the end (null) */
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const csv_cb = (d:string|null) => {
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if(d == null) return;
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/* The strings include line endings, so raw write ops should be used */
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Deno.stdout.write(new TextEncoder().encode(d));
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};
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/* Fetch https://sheetjs.com/pres.numbers, parse, and get first worksheet */
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const ab = await (await fetch("https://sheetjs.com/pres.numbers")).arrayBuffer();
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const wb = read(ab, { dense: true });
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const ws = wb.Sheets[wb.SheetNames[0]];
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/* Create and start CSV stream */
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sheet_to_csv_cb(ws, csv_cb).resume();
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