fix(reduce-function): make reduce actually usable

Reduce has to take a curried function so that it can be easily used
kantord · Oct 22, 2018 · 02672e0 · 02672e0
1 parent c370308
commit 02672e0
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Showing 4 changed files with 98 additions and 4 deletions.
diff --git a/src/__tests__/__snapshots__/interpreter.test.js.snap b/src/__tests__/__snapshots__/interpreter.test.js.snap
@@ -119,6 +119,8 @@ exports[`interpreter correct target code null 1`] = `"(function(_) { return (fun
 
 exports[`interpreter correct target code null: true 1`] = `"(function(_) { return (function(input) { return [null,true]})})"`;
 
+exports[`interpreter correct target code reduce ($a => $b => $a + $b): 0 1`] = `"(function(_) { return (function(input) { return _.reduce([((function(a) {_ = _.assign('a', a, _); return (function(b) {_ = _.assign('b', b, _); return _.get('a')+_.get('b')})})),0])(input)})})"`;
+
 exports[`interpreter correct target code sortBy \\.age | map \\.name 1`] = `"(function(_) { return (function(input) { return (function (input) {return _.map((function(input) {return input.name}))(input)})(_.sortBy((function(input) {return input.age}))(input))})})"`;
 
 exports[`interpreter correct target code true 1`] = `"(function(_) { return (function(input) { return true})})"`;
@@ -4541,6 +4543,92 @@ Object {
 }
 `;
 
+exports[`interpreter correct target tree reduce ($a => $b => $a + $b): 0 1`] = `
+Object {
+  "status": true,
+  "value": Object {
+    "name": "functionCall",
+    "value": Object {
+      "left": Object {
+        "name": "identifier",
+        "value": "reduce",
+      },
+      "right": Object {
+        "name": "tuple",
+        "value": Array [
+          Object {
+            "name": "parentheses",
+            "value": Object {
+              "end": Object {
+                "column": 28,
+                "line": 1,
+                "offset": 27,
+              },
+              "name": "lambda",
+              "start": Object {
+                "column": 9,
+                "line": 1,
+                "offset": 8,
+              },
+              "value": Object {
+                "definition": Object {
+                  "end": Object {
+                    "column": 28,
+                    "line": 1,
+                    "offset": 27,
+                  },
+                  "name": "lambda",
+                  "start": Object {
+                    "column": 15,
+                    "line": 1,
+                    "offset": 14,
+                  },
+                  "value": Object {
+                    "definition": Object {
+                      "name": "binaryOperation",
+                      "value": Array [
+                        Object {
+                          "name": "variable",
+                          "value": "$a",
+                        },
+                        Object {
+                          "end": Object {
+                            "column": 25,
+                            "line": 1,
+                            "offset": 24,
+                          },
+                          "name": "primitive",
+                          "start": Object {
+                            "column": 24,
+                            "line": 1,
+                            "offset": 23,
+                          },
+                          "value": "+",
+                        },
+                        Object {
+                          "name": "variable",
+                          "value": "$b",
+                        },
+                      ],
+                    },
+                    "variable": "b",
+                  },
+                },
+                "variable": "a",
+              },
+            },
+          },
+          Object {
+            "name": "primitive",
+            "value": "0",
+          },
+        ],
+      },
+    },
+  },
+}
+`;
+
 exports[`interpreter correct target tree sortBy \\.age | map \\.name 1`] = `
 Object {
   "status": true,

diff --git a/src/__tests__/builtins.test.js b/src/__tests__/builtins.test.js
@@ -71,7 +71,7 @@ describe('built ins', () => {
 
   describe('reduce', () => {
     it('returns correct value', () => {
-      const x = (a, b) => a * b + 1; // eslint-disable-line
+      const x = a => b => a * b + 1; // eslint-disable-line
       expect(reduce([x, 4])([1, 2])).toEqual(11)
     })
   })

diff --git a/src/__tests__/interpreter.test.js b/src/__tests__/interpreter.test.js
@@ -296,6 +296,11 @@ const tests = [
     sourceCode: `map $foo => [$foo]`,
     input: [1, 2],
     output: [[1], [2]]
+  },
+  {
+    sourceCode: `reduce ($a => $b => $a + $b): 0`,
+    input: [1, 2, -1, 3],
+    output: 5
   }
 ]
 

diff --git a/src/builtins.js b/src/builtins.js
@@ -82,9 +82,10 @@ export default {
 
   reverse: (input: Array<mixed>): Array<mixed> => input.slice().reverse(),
 
-  reduce: ([f, x]: [(mixed) => mixed, mixed]): ((Array<mixed>) => mixed) => (
-    input: Array<mixed>
-  ): mixed => input.reduce(f, x),
+  reduce: ([f, x]: [(mixed) => mixed => mixed, mixed]): ((
+    Array<mixed>,
+  ) => mixed) => (input: Array<mixed>): mixed =>
+    input.reduce((a: mixed, b: mixed): mixed => f(a)(b), x),
 
   length: (input: Array<mixed>): number => input.length,