Add context to try fallbacks

Author: TotalTechGeek

defaultMethods.js

@@ -293,7 +293,9 @@ const defaultMethods = {
       let lastError
       for (let i = 0; i < arr.length; i++) {
         try {
-          item = executeInLoop ? engine.run(arr[i], _1, { above: _2 }) : arr[i]
+          // Todo: make this message thing more robust.
+          if (lastError) item = engine.run(arr[i], { error: lastError.message || lastError.constructor.name }, { above: [null, _1, _2] })
+          else item = executeInLoop ? engine.run(arr[i], _1, { above: _2 }) : arr[i]
           return item
         } catch (e) {
           // Do nothing
@@ -312,7 +314,9 @@ const defaultMethods = {
       let lastError
       for (let i = 0; i < arr.length; i++) {
         try {
-          item = executeInLoop ? await engine.run(arr[i], _1, { above: _2 }) : arr[i]
+          // Todo: make this message thing more robust.
+          if (lastError) item = await engine.run(arr[i], { error: lastError.message || lastError.constructor.name }, { above: [null, _1, _2] })
+          else item = executeInLoop ? await engine.run(arr[i], _1, { above: _2 }) : arr[i]
           return item
         } catch (e) {
           // Do nothing
@@ -970,11 +974,11 @@ defaultMethods['/'].compile = function (data, buildState) {
   if (Array.isArray(data)) {
     return `(${data.map((i, x) => {
     let res = numberCoercion(i, buildState)
-    if (x) res = `(${res}|| (() => { throw new Error() })() )`
+    if (x) res = `(${res}|| (() => { throw new Error('NaN') })() )`
     return res
   }).join(' / ')})`
   }
-  return `(${buildString(data, buildState)}).reduce((a,b) => (+precoerceNumber(a))/(+precoerceNumber(b) || (() => { throw new Error() })() ))`
+  return `(${buildString(data, buildState)}).reduce((a,b) => (+precoerceNumber(a))/(+precoerceNumber(b) || (() => { throw new Error('NaN') })() ))`
 }
 // @ts-ignore Allow custom attribute
 defaultMethods['*'].compile = function (data, buildState) {

suites/try.json

@@ -61,5 +61,45 @@
         },
         "result": 10,
         "data": null
+    },
+    {
+        "description": "The context switches for the try coalescing to the previous error",
+        "rule": {
+            "try": [
+                { "if": [true, { "error": "Some error" }, null] },
+                { "val": [] }
+            ]
+        },
+        "result": { "error": "Some error"},
+        "data": null
+    },
+    {
+        "description": "Try can work further up the AST with Exceptions, and return the error",
+        "rule": {
+            "try": [{
+                "if": [
+                    true,
+                    { "map": [[1,2,3], {"/": [0, 0] }]},
+                    null
+                ]
+            }, { "val": [] }]
+        },
+        "result": { "error": "NaN" },
+        "data": null
+    },
+    "# Not Proposed",
+    {
+        "description": "Try can work further up the AST with Exceptions; Grabbing other Context value",
+        "rule": {
+            "try": [{
+                "if": [
+                    true,
+                    { "map": [[1,2,3], {"/": [0, 0] }]},
+                    null
+                ]
+            }, { "val": [[2], "fallback"] }]
+        },
+        "result": "Hello",
+        "data": { "fallback": "Hello" }
     }
 ]