Support null or false to omit header row

[jeffandersen]

In my case, I had an array of objects but did not want the header row.

This change allows for options.header to be set to null or false to explicitly omit the header row.

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[aichbauer]

Hello,

thanks for your contribution 👍

I have to dig into the project again. But just for clarification, doesnt !header does the same as header === undefined but include things like 0, null, etc...

[jeffandersen]

The intent is to allow Null or False (an explicit negative) to signify not to include the header, but when the value is not specified at all (undefined)... to automatically include the default (the current behaviour)

[aichbauer]

Ah okay, so if its null or undefined it should skip this line and not go into the if stmt.

[jeffandersen]

By changing the logic to identify an explicit false we're able to have the following:

const dataArrays = [ {a: 1, b: 2}, {a: 3, b: 4} ];
const csvFromArrayOfArrays = convertArrayToCSV(dataArrays, { header: false });

With output of:

1,2
3,4

Versus the normal behavior of:

const dataArrays = [ {a: 1, b: 2}, {a: 3, b: 4} ];
const csvFromArrayOfArrays = convertArrayToCSV(dataArrays);

With output of:

a,b
1,2
3,4

[aichbauer]

I see, that looks legit. I have to take a look myself, but overall I am looking forward to getting this PR merged.