toRecords fails to convert pl.Date values

[kymckay]

Have you tried latest version of polars?

• yes

What version of polars are you using?

• 0.7.2

What operating system are you using polars on?

• Debian 12

What node version are you using

• node 18.13.0

Describe your bug.

• With a pl.Date column in the data frame, using the toRecords function produces objects which have dates at the unix epoch.

What are the steps to reproduce the behavior?

import pl from "nodejs-polars";

let df = pl.DataFrame({
  date: [new Date()],
});

df = df.withColumn(pl.col("date").cast(pl.Date).alias("date"));

console.log(df.toString());
console.log(df.toRecords());

What is the actual behavior?

shape: (1, 1)
┌────────────┐
│ date       │
│ ---        │
│ date       │
╞════════════╡
│ 2023-03-09 │
└────────────┘

{date: Thu Jan 01 1970 01:00:19 GMT+0100 (Greenwich Mean Time)}

What is the expected behavior?

shape: (1, 1)
┌────────────┐
│ date       │
│ ---        │
│ date       │
╞════════════╡
│ 2023-03-09 │
└────────────┘

{date: Thu Mar 09 2023 00:00:00 GMT+0100 (Greenwich Mean Time)}

[Bidek56]

This works in 0.8.0:

let df = pl.DataFrame({
  date: [new Date()],
});

df = df.withColumn(pl.col("date").date.strftime("%Y-%m-%d").alias("date"));

console.log(df.toString());
console.log(df.toRecords());

shape: (1, 1)
┌────────────┐
│ date       │
│ ---        │
│ str        │
╞════════════╡
│ 2023-06-18 │
└────────────┘
[ { date: '2023-06-18' } ]

[kymckay]

I think you have misunderstood, as your example is different since it's just converting a pl.Datetime column into strings.

I'm interested in storing pl.Date type in the dataframe, which should map to Date objects in the records form (pl.Datetime works correctly and can be used as a workaround, but I don't need that precision, just the date).

[Bidek56]

The code above works fine in 0.8.2, please re-open is this still an issue. Thx