Separate out the val proposal

Author: TotalTechGeek

defaultMethods.js

@@ -203,6 +203,35 @@ const defaultMethods = {
       }
     }
   },
+  // Adding this to spec something out, not to merge it quite yet
+  val: {
+    method: (args, context, above) => {
+      let result = context
+      let start = 0
+      if (Array.isArray(args[0]) && args[0].length === 1) {
+        start++
+        const climb = +Math.abs(args[0][0])
+        let pos = 0
+        for (let i = 0; i < climb; i++) {
+          result = above[pos++]
+          if (i === above.length - 1 && Array.isArray(result)) {
+            above = result
+            result = result[0]
+            pos = 1
+          }
+        }
+      }
+
+      for (let i = start; i < args.length; i++) {
+        if (args[i] === null) continue
+        if (result === null || result === undefined) return null
+        result = result[args[i]]
+      }
+      if (typeof result === 'undefined') return null
+      return result
+    },
+    deterministic: false
+  },
   var: (key, context, above, engine) => {
     let b
     if (Array.isArray(key)) {
@@ -539,7 +568,7 @@ function createArrayIterativeMethod (name, useTruthy = false) {
       }
 
       const method = build(mapper, mapState)
-      const aboveArray = method.aboveDetected ? buildState.compile`[{ item: null }, context, above]` : buildState.compile`null`
+      const aboveArray = method.aboveDetected ? buildState.compile`[{ item: null, index: x }, context, above]` : buildState.compile`null`
 
       if (async) {
         if (!isSyncDeep(mapper, buildState.engine, buildState)) {

suites/val.json

@@ -0,0 +1,72 @@
+[
+    "Test Specification for val",
+    {
+        "description": "Fetches a value from an empty key",
+        "rule": { "val": "" },
+        "data": { "" : 1 },
+        "result": 1
+    },
+    {
+        "description": "Fetches a value from a nested empty key",
+        "rule": { "val": ["", ""] },
+        "data": { "" : { "": 2 } },
+        "result": 2
+    },
+    {
+        "description": "Fetches a value from a doubly nested empty key",
+        "rule": { "val": ["", "", ""] },
+        "data": { "" : { "": { "": 3 } } },
+        "result": 3
+    },
+    {
+        "description": "Fetches a value from a key that is purely a dot",
+        "rule": { "val": "." },
+        "data": { "." : 20 },
+        "result": 20
+    },
+    {
+        "description": "Fetches the entire context",
+        "rule": { "val": null },
+        "data": { "": 21 },
+        "result": { "": 21 }
+    },
+    {
+        "description": "Fetches the entire context for a nested key",
+        "rule": { "val": "" },
+        "data": { "": { "": 22 } },
+        "result": { "": 22 }
+    },
+    {
+        "description": "Using val in a map (remember that null gets the current context, not empty string)",
+        "rule": { "map": [[1,2,3], { "+": [{ "val": null }, 1] }] },
+        "data": null,
+        "result": [2,3,4]
+    },
+    {
+        "description": "Using val in a map (and remember [null] and null are the same)",
+        "rule": { "map": [[1,2,3], { "+": [{ "val": [null] }, 1] }] },
+        "data": null,
+        "result": [2,3,4]
+    },
+    "Testing out scopes",
+    {
+        "description": "Climb up to get adder",
+        "rule": { "map": [[1,2,3], { "+": [{ "val": null }, { "val": [[-2], "adder"] }] }] },
+        "data": { "adder": 10 },
+        "result": [11,12,13]
+    },
+    {
+        "description": "Climb up to get index",
+        "rule": { "map": [[1,2,3], { "+": [{ "val": null }, { "val": [[-1], "index"] }] }] },
+        "data": { "adder": 10 },
+        "result": [1,3,5]
+    },
+    {
+        "description": "Nested get adder",
+        "rule": {
+            "map": [["Test"], { "map": [[1,2,3], { "+": [{"val": null}, {"val": [[-4], "adder"]}] }]} ]
+        },
+        "data": { "adder": 10 },
+        "result": [[11,12,13]]
+    }
+]