feat(json-expression): 🎸 add values operator

streamich · Aug 28, 2023 · be2d0fa · be2d0fa
1 parent e713ece
commit be2d0fa
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diff --git a/src/json-expression/__tests__/jsonExpressionUnitTests.ts b/src/json-expression/__tests__/jsonExpressionUnitTests.ts
@@ -1580,6 +1580,22 @@ export const jsonExpressionUnitTests = (
         );
       });
     });
+
+    describe('values', () => {
+      test('returns empty array for empty object', () => {
+        check(['values', {}], []);
+      });
+
+      test('returns values of an object', () => {
+        check(['values', {foo: 1}], [1]);
+      });
+
+      test('throws on invalid operand count', () => {
+        expect(() => check(['values', 'a', 'b'] as any, false)).toThrowErrorMatchingInlineSnapshot(
+          `""values" operator expects 1 operands."`,
+        );
+      });
+    });
   });
 
   describe('Branching operators', () => {

diff --git a/src/json-expression/operators/object.ts b/src/json-expression/operators/object.ts
@@ -17,4 +17,19 @@ export const objectOperators: types.OperatorDefinition<any>[] = [
       return new Expression(js);
     },
   ] as types.OperatorDefinition<types.ExprKeys>,
+
+  [
+    'values',
+    [],
+    1,
+    (expr: types.ExprValues, ctx) => {
+      const operand = ctx.eval(expr[1], ctx);
+      return util.values(operand);
+    },
+    (ctx: types.OperatorCodegenCtx<types.ExprValues>): ExpressionResult => {
+      ctx.link(util.values, 'values');
+      const js = `values(${ctx.operands[0]})`;
+      return new Expression(js);
+    },
+  ] as types.OperatorDefinition<types.ExprValues>,
 ];
diff --git a/src/json-expression/types.ts b/src/json-expression/types.ts
@@ -179,9 +179,11 @@ export type ExprF64 = BinaryExpression<'f64'>;
 // Object expressions
 export type ObjectExpression = 
   | ExprKeys
+  | ExprValues
   | ExprIn;
 
 export type ExprKeys = UnaryExpression<'keys'>;
+export type ExprValues = UnaryExpression<'values'>;
 export type ExprIn = [fn: 'in', what: unknown, list: unknown];
 
 // Bitwise expressions

diff --git a/src/json-expression/util.ts b/src/json-expression/util.ts
@@ -50,6 +50,14 @@ export const asObj = (value: unknown): object => {
 export const keys = (value: unknown): string[] =>
   Object.keys(asObj(value));
 
+export const values = (value: unknown): unknown[] => {
+  const values: unknown[] = [];
+  const theKeys = keys(value);
+  const length = theKeys.length;
+  for (let i = 0; i < length; i++) values.push((value as any)[theKeys[i]]);
+  return values;
+};
+
 export const u8 = (bin: unknown, pos: unknown) => {
   const buf = asBin(bin);
   const index = int(pos);