mholt/PapaParse

row.meta.cursor in step always same value when parsing in worker mode

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#465 opened on Mar 16, 2018

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 (8 comments) (2 reactions) (0 assignees)JavaScript (1,157 forks)batch import
enhancementhelp wanted

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Description

Not sure if this is a bug or simply a limitation of parsing in worker mode, but when I parse a (local) file in worker mode, the row.meta.cursor always points to the end of the file:

Papa.parse(file, {
  header: true,
  worker: true, // << worker is true
  step: (row, parser) => {
    console.log(row.meta.cursor, file.size);
    // => logs "677403 677403" 8973 times
  },
});

Papa.parse(file, {
  header: true,
  worker: false, // << worker is false
  step: (row, parser) => {
    console.log(row.meta.cursor, file.size);
    // => logs increasisng number upto filesize as expected
  },
});

Is there any way to get the cursor (or anything else that can be used as a progress-indicator) when parsing in worker mode?

Contributor guide

Research direction
Inspect the worker postMessage implementation and trace how cursor is passed in worker mode.
Tech stack
javascript
Domain
frontend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
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Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JavaScriptGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75