forEachChild improvements

[killmenot]

ewd-document-store/lib/proto/forEach.js

Line 123 in 55179cb

if (callback) quit = callback.call(this, result, gnode);

• pass index after gnode
• accept thisArg to forEachChild method like Array.forEach does

[killmenot]

Same can be applied for forEachLeafNode

[robtweed]

I don't think there's a real use case for either suggestion. forEachChild is iterating through the subscript values at a particular level of subscripting within a Global - the only 2 relevant values you need are the next subscript value and its corresponding DocumentNode, from which you can derive any other information.

[killmenot]

The simple use case for index can be printing number of item without i variable declaration. I'm sure there are other cases that can be.

before:

var index = 0;

myDoc.forEachChild(function (nodeName, node) {
  console.log(`{index}: {nodeName}`)
  index++;
})

after

myDoc.forEachChild(function (nodeName, node, index) {
  console.log(`{index}: {nodeName}`)
})

thisArg is not common used case. I think we can skip it.