Merge pull request #4 from KaiVolland/handle-bad-inputs

Introduces handling of bad/empty input to read and write method

Author: KaiVolland

src/CqlParser.spec.ts

@@ -1,4 +1,5 @@
 import { CqlParser } from './CqlParser';
+import { Filter } from 'geostyler-style';
 
 describe('CqlParser', () => {
   let cqlParser: CqlParser;
@@ -15,6 +16,12 @@ describe('CqlParser', () => {
     it('is defined', () => {
       expect(cqlParser.read).toBeDefined();
     });
+    it('returns undefined for empty strings', () => {
+      const cqlFilter1 = undefined;
+      const cqlFilter2 = '';
+      expect(cqlParser.read(cqlFilter1)).toBeUndefined();
+      expect(cqlParser.read(cqlFilter2)).toBeUndefined();
+    });
     it('can read String Comparison Filters', () => {
       const cqlFilter = 'Name = Peter';
       const got = cqlParser.read(cqlFilter);
@@ -62,6 +69,14 @@ describe('CqlParser', () => {
     it('is defined', () => {
       expect(cqlParser.write).toBeDefined();
     });
+    it('returns undefined for illegal filters', () => {
+      const cqlFilter1 = undefined;
+      const cqlFilter2: Filter = ['=='];
+      const cqlFilter3: Filter = [];
+      expect(cqlParser.write(cqlFilter1)).toBeUndefined();
+      expect(cqlParser.write(cqlFilter2)).toBeUndefined();
+      expect(cqlParser.write(cqlFilter3)).toBeUndefined();
+    });
     it('can write String Comparison Filters', () => {
       const geoStylerFilter = ['==', 'Name', 'Peter'];
       const got = cqlParser.write(geoStylerFilter);

src/CqlParser.ts

@@ -327,20 +327,30 @@ export class CqlParser {
     return result;
   }
 
-  read(text: string): Filter {
+  read(text: string | undefined): Filter | undefined {
     const {
       buildAst,
       tokenize
     } = this;
+
+    if (!text || text.length === 0) {
+      return undefined;
+    }
+
     return buildAst(tokenize(text));
   }
 
-  write(filter: Filter): string | undefined {
+  write(filter: Filter | undefined): string | undefined {
     const {
       operatorReverseMap,
       combinationOperatorsReverseMap,
       write
     } = this;
+
+    if (!Array.isArray(filter) || filter.length < 2) {
+      return undefined;
+    }
+
     const operator = filter[0];
     const cqlOperator = operatorReverseMap[operator];
     switch (operator) {