feat(eval): adds evaluation for simple binop expressions

2 files changed, 64 insertions, 0 deletions

diff --git a/tests/calc.spec.ts b/tests/calc.spec.ts
new file mode 100644
index 0000000..a4e11cd
--- /dev/null
+++ b/tests/calc.spec.ts
@@ -0,0 +1,46 @@
+import { EvalActions, EvalValue, evalExpr } from '../src/eval'
+import { parseExpr } from '../src/parser'
+import { matchString } from '../src/utils/adt'
+
+describe('calc', () => {
+  const variables = (name: string) =>
+    matchString(name, {
+      '--test-8rem': () => '8rem',
+      _: () => {},
+    })
+  const actions: EvalActions = {
+    addClass: jest.fn(),
+    removeClass: jest.fn(),
+    delay: jest.fn(),
+    jsEval: jest.fn(),
+    loadCssx: jest.fn(),
+    getVariable: jest.fn(variables),
+    updateVariable: jest.fn(),
+    setAttribute: jest.fn(),
+    getAttribute: jest.fn(),
+    withEvent: jest.fn(),
+    getFormData: jest.fn(),
+    sendRequest: jest.fn(),
+    addChildren: jest.fn(),
+    removeElement: jest.fn(),
+    callMethod: jest.fn(),
+    evaluateInScope: jest.fn(),
+  }
+
+  describe.each([
+    ['calc(8rem)', EvalValue.Number(128)],
+    ['calc(5 + 8)', EvalValue.Number(13)],
+    ['calc(5 * 8 + 1)', EvalValue.Number(41)],
+    ['calc(5 * (8 + 1))', EvalValue.Number(45)],
+    ['calc(5px * (8rem + 1))', EvalValue.Number(645)],
+    ['calc(5px * 8rem/2 + 1)', EvalValue.Number(321)],
+    ['calc(var(--test-8rem))', EvalValue.Number(128)],
+    ['calc(var(--test-1))', EvalValue.Number(0)], // Var not found
+    ['calc(5px * var(--test-8rem)/2 + 1)', EvalValue.Number(321)],
+  ])('when given "%s"', (expr, expected) => {
+    it('should evaluate the result of math', async () => {
+      const evalValue = await evalExpr(parseExpr(expr), actions)
+      expect(evalValue).toEqual(expected)
+    })
+  })
+})
diff --git a/tests/parser.spec.ts b/tests/parser.spec.ts
index 494bb51..16480e6 100644
--- a/tests/parser.spec.ts
+++ b/tests/parser.spec.ts
@@ -267,5 +267,23 @@ describe('parser', () => {
         }),
       ])
     })
+
+    it('parses calc expression with vars', () => {
+      expect(parse(`calc(5px * var(--value))`)).toEqual([
+        Expr.Call({
+          name: 'calc',
+          args: [
+            Expr.BinOp({
+              op: '*',
+              left: Expr.LiteralNumber({ value: 5, unit: 'px' }),
+              right: Expr.Call({
+                name: 'var',
+                args: [Expr.VarIdentifier('--value')],
+              }),
+            }),
+          ],
+        }),
+      ])
+    })
   })
 })