Do not remove zeroes from tree paths

.changeset/big-plums-wave.md

@@ -0,0 +1,5 @@
+---
+'futil': patch
+---
+
+Do not remove zeroes from tree paths

src/array.js

@@ -18,7 +18,9 @@ let last = _.takeRight(1)
  * @signature joinString -> [string1, string2, ...stringN] -> string1 + joinString + string2 + joinString ... + stringN
  * @typescript {(join: string, x: any[]) => string}
  */
-export let compactJoin = _.curry((join, x) => _.compact(x).join(join))
+export let compactJoin =
+  // TODO: (major) Do not use `_.compact` as removes the number 0.
+  _.curry((join, x) => _.compact(x).join(join))
 
 /**
  * Compacts and joins an array with `.`
@@ -171,6 +173,24 @@ export let dotEncoder = encoder('.')
  */
 export let slashEncoder = encoder('/')
 
+// The name "pack" is tentative. It's intended to behave as `_.compact` without
+// removing the number 0.
+let pack = _.remove(
+  (x) => x === undefined || x === null || x === false || x === ''
+)
+
+// Internal use until we release next major
+let __internalEncoder = (separator) => ({
+  encode: _.flow(pack, _.join(separator)),
+  decode: _.split(separator),
+})
+
+// Internal use until we release next major
+export let __internalDotEncoder = __internalEncoder('.')
+
+// Internal use until we release next major
+export let __internalSlashEncoder = __internalEncoder('/')
+
 /**
  * Takes a predicate function and an array, and returns an array of arrays where each element has one or more elements of the original array. Similar to Haskell's [groupBy](http://zvon.org/other/haskell/Outputlist/groupBy_f.html).
 

src/collection.js

@@ -59,6 +59,7 @@ export let insertAtIndex = _.curry((index, val, collection) =>
  * @signature (fn, collection) -> collection
  */
 export let compactMap = _.curry((fn, collection) =>
+  // TODO: (major) Do not use `_.compact` as removes the number 0.
   _.flow(_.map(fn), _.compact)(collection)
 )
 

src/string.js

@@ -27,6 +27,8 @@ export const quote = wrap('"', '"')
  * @signature 'asdf' -> '(asdf)'
  */
 export const parens = wrap('(', ')')
+
+// TODO: (major) Do not use `_.compact` as removes the number 0.
 export const concatStrings = _.flow(_.compact, _.map(_.trim), _.join(' '))
 
 /**

src/tree.js

@@ -7,7 +7,7 @@
 
 import _ from 'lodash/fp'
 import { findIndexed } from './conversion'
-import { pushOn, dotEncoder, slashEncoder } from './array'
+import { pushOn, __internalDotEncoder, __internalSlashEncoder } from './array'
 
 /**
  * A default check if something can be traversed - currently it is arrays and plain objects.
@@ -239,7 +239,7 @@ export let treeValues = (x, i, xs) => [x, ...xs]
  * @signature (build, encoder) -> treePathBuilderFunction
  */
 export let treePath =
-  (build = treeKeys, encoder = dotEncoder) =>
+  (build = treeKeys, encoder = __internalDotEncoder) =>
   (...args) =>
     (encoder.encode || encoder)(build(...args).reverse())
 
@@ -249,7 +249,7 @@ export let treePath =
  * @signature prop -> treePathBuilderFunction
  */
 export let propTreePath = (prop) =>
-  treePath(_.flow(treeValues, _.map(prop)), slashEncoder)
+  treePath(_.flow(treeValues, _.map(prop)), __internalSlashEncoder)
 
 /**
  * Creates a flat object with a property for each node, using `buildPath` to determine the keys. `buildPath` takes the same arguments as a tree walking iteratee. It will default to a dot tree path.

test/tree.spec.js

@@ -22,6 +22,12 @@ describe('Tree Functions', () => {
     }
     expect(F.traverse(x)).to.deep.equal(x)
   })
+  describe('treePath', () => {
+    it('should not remove zeroes', () => {
+      let path = F.treePath()(null, 'first', [], ['second', 0, 'third'])
+      expect(path).to.equal('third.0.second.first')
+    })
+  })
   describe('walk', () => {
     let x = {
       a: 1,