First column is blank in v5 when indexing into jagged arrays rather than arrays of objects

[mungojam]

Which version of React JS are you using?

✅ Officially supported ✅

• v15.4.x

⚠️ Not officially supported, expect warnings ⚠️

• v15.5.x
• v15.6.x

☣️ Not officially supported, expect warnings and errors ☣️

• v16.x.x

---

Which browser are you using?

✅ Officially supported ✅

• IE 9 / IE 10 / IE 11
• Edge
• Chrome

⚠️ Not officially supported, but "should work" ⚠️

• Firefox
• Safari

---

I'm submitting a ...

• 🐛 Bug Report
• 💡 Feature Request

👋 Need general support? Not sure about how to use React itself, or how to get started with the Grid?
Please do not submit support request here. Instead see

https://github.com/adazzle/react-data-grid/blob/master/CONTRIBUTING.md

---

Issue Details

When using v4, I was able to have my backing data stored as a jagged/nested array, with the outer dimension for the rows and the inner dimension for the columns. I then used the column index as the key for each column. This made it easy to work with data coming as an array of column headings plus an array of arrays with the data in.

With v5 however, the first column is coming out blank:

Here's the MRE:

import React from 'react';

import ReactDataGrid from 'react-data-grid';

export default () => {
  const rows = [];
  for (let i = 1; i < 20; i++) {
    rows.push([i, 'Title ' + i, i * 20]
    );
  }

  const columns = [
    { key: 0, name: 'ID' },
    { key: 1, name: 'Title' },
    { key: 2, name: 'Count' } ];

  return (
    <div className="App">
      <ReactDataGrid
        columns={columns}
        rowGetter={i => rows[i]}
        rowsCount={rows.length}
        minHeight={500} />
    </div>
  );
}

[mungojam]

When I switch around the keys, it's evident that it is actually a key of 0 is the problem:

  const columns = [
    { key: 1, name: 'ID' },
    { key: 0, name: 'Title' },
    { key: 2, name: 'Count' } ];

[mungojam]

It all seems to revolve around this line:

react-data-grid/packages/react-data-grid/src/Row.js

Line 69 in f505d00

value: this.getCellValue(key || i),

0 || something results in something, not 0. And so it turns out that in v4 this was falling back on i, which happened to be just what I wanted. I could have taken out the keys altogether.

In v5 however, i is undefined for some reason. So I guess there are maybe two issues here, treatment of 0 and lack of i. I'll try and dig into why i is undefined

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Please reopen this if you feel it has been incorrectly closed and we will do our best to look into it. Thank you for your contributions.

[mungojam]

There's still a remaining bug for any column key of 0 if it isn't the first column, but that will be a pretty rare scenario and the main issue is fixed