Date support

[symbyte]

Would it be possible to have javascript date support? From the source of structure.js it looks like it is at least partially supported, but is there anything blocking having the fields.js script resolve date types in addition to numbers, strings, and booleans?

Willing to submit a PR, but didn't want to waste my time if it wasn't possible/desired.

[mhkeller]

@symbyte I have a fork at https://github.com/mhkeller/dbf/ that includes some of the unmerged PRs for this. If you wanted to add date support to that fork that would be great.

[bakednevada]

@symbyte Column resolution is based on some typeof magic, but you can't detect dates that way. Dates have to be resolved with instanceof. Took a grand total of about 5 minutes to patch it in:

diff --git a/json2dbf.js b/json2dbf.js
index 758d2a5..a0ed2e4 100644
--- a/json2dbf.js
+++ b/json2dbf.js
@@ -2,7 +2,7 @@ var dbf = require('./'),
     fs = require('fs');
 
 var buf = dbf.structure([
-    {foo:'bar',noo:10},
+    {foo:'bar',noo:new Date()},
     {foo:'louie'}
 ]);
 
diff --git a/src/fields.js b/src/fields.js
index 5961b76..27c9285 100644
--- a/src/fields.js
+++ b/src/fields.js
@@ -4,6 +4,7 @@ var types = {
     string: 'C',
     number: 'N',
     boolean: 'L',
+    date: 'D',
     // type to use if all values of a field are null
     null: 'C'
 };
@@ -36,7 +37,7 @@ function inherit(a, b) {
 
 function obj(_) {
     var fields = {}, o = [];
-    for (var p in _) fields[p] = _[p] === null ? 'null' : typeof _[p];
+    for (var p in _) fields[p] = _[p] === null ? 'null' : _[p] instanceof Date ? 'date' : typeof _[p];
     for (var n in fields) {
         var t = types[fields[n]];
         if(t){
diff --git a/src/lib.js b/src/lib.js
index 0c7ff80..5b60ed0 100644
--- a/src/lib.js
+++ b/src/lib.js
@@ -31,3 +31,8 @@ module.exports.writeField = function writeField(view, fieldLength, str, offset)
     }
     return offset;
 };
+
+module.exports.writeDate = function(date) {
+    if(!date || isNaN(date.getTime())) return "        ";
+    return ("0000"+date.getFullYear()).slice(-4) + ("00"+(date.getMonth()+1)).slice(-2) + ("00"+date.getDate()).slice(-2);
+};
diff --git a/src/structure.js b/src/structure.js
index 4b02783..9bc286d 100644
--- a/src/structure.js
+++ b/src/structure.js
@@ -29,7 +29,7 @@ module.exports = function structure(data, meta) {
     view.setUint8(0, 0x03);
     // date of last update
     view.setUint8(1, now.getFullYear() - 1900);
-    view.setUint8(2, now.getMonth());
+    view.setUint8(2, now.getMonth()+1);
     view.setUint8(3, now.getDate());
     // number of records
     view.setUint32(4, data.length, true);
@@ -75,7 +75,7 @@ module.exports = function structure(data, meta) {
                 // date
                 case 'D':
                     offset = lib.writeField(view, 8,
-                        lib.lpad(val.toString(), 8, ' '), offset);
+                        lib.writeDate(val), offset);
                     break;
 
                 // number

Checked against the DBF reader from https://www.npmjs.com/package/xlsx and it appears to work correctly.

[jeff-tenhave]

@bakednevada Are you planning on submitting a PR with that change? I'd like to avoid forking if possible so it would be great if we could get that change in here. I could submit a PR if you don't plan to.

[bakednevada]

@jeff-tenhave go ahead, but I recommend also submitting a PR to the @mhkeller branch, as his branch seems to be ahead of the mainline

[mhkeller]

It would be great if this were merged into here as opposed to a fork. There are a few outstanding PRs that would also be great. I made a fork because it seemed this repo hasn't been maintained in the last six months and I needed a fix for another lib that depends on this.

@tmcw I don't think you're at Mapbox anymore. Is there someone you could alert there who might be able to take this one over?

[bakednevada]

If the name is lost, I wouldn't mind occasionally helping on a fork. We could organize with a github org like dbfjs and an npm module dbfjs since that name is available on github and npm. And if we are able to obtain access to publishing under the name, we could have dbf merely wrap dbfjs.

[tmcw]

I'm not sure. I can probably poke @davidtheclark without him getting mad at me :)

[mhkeller]

Tom you have given the world so much, how could one ever be mad ;)

[tmcw]

Well, next up, poking @mikelmaron - anyone over there want to merge some pull requests? There are many others, all waiting for that green button.

[davidtheclark]

Hi @tmcw and everyone. I'm asking around to try to sort out whether anybody internal wants to take on this project. If I can't figure out anything definite this week, I'll learn what's going on here and merge some PRs next week. Hope that works for everyone.

[jeff-tenhave]

I've opened a PR with @bakednevada 's changes.

[davidtheclark]

I think the best thing moving forward would be for folks to switch over to @mhkeller's fork. We would then add a note to the readme of this repo recommending that people go use that fork. Once the fork is released on npm, we can deprecate the dbf package and point users to the new one.

@mhkeller: Does that sound ok with you? Interested in taking over maintenance? If you're not and anybody else in this thread is, please let me know.

cc @mikelmaron @kathleenlu09

[mhkeller]

@davidtheclark i unfortunately wouldn't have the expertise to maintain this one.

[davidtheclark]

Ok, @mhkeller.

I added a note to the README saying that this project is looking for a new maintainer: https://github.com/mapbox/dbf/blob/master/README.md#looking-for-new-maintainers. I plan to sit on it a bit to see if anyone bites before taking any more steps.