Support regexp in 'StringStream.split' method

Author: f1ames

src/streams/string-stream.ts

@@ -7,7 +7,9 @@ export class StringStream extends DataStream<string> {
         return new StringStream();
     }
 
-    split(splitBy: string) {
+    split(splitBy: string): StringStream;
+    split(splitBy: RegExp): StringStream;
+    split(splitBy: string | RegExp): StringStream {
         const splitter = this.getSplitter(splitBy);
         const onEndYield = () => ({ yield: splitter.emitLastValue, value: splitter.lastValue });
 
@@ -28,18 +30,20 @@ export class StringStream extends DataStream<string> {
         return super.flatMap(callback, ...args) as StringStream;
     }
 
-    private getSplitter(splitBy: string) {
+    private getSplitter(splitBy: string | RegExp) {
         const result: any = {
             emitLastValue: false,
             lastValue: ""
         };
+        const testFn = toString.call(splitBy) === "[object RegExp]"
+            ? (chunk: string) => (splitBy as RegExp).test(chunk) : (chunk: string) => chunk.includes(splitBy as string);
 
         result.fn = (chunk: string): string[] => {
             const tmpChunk = `${result.lastValue}${chunk}`;
 
             result.emitLastValue = true;
 
-            if (!tmpChunk.includes(splitBy)) {
+            if (!testFn(tmpChunk)) {
                 result.lastValue = tmpChunk;
                 return [];
             }

test/unit/streams/string/split.spec.ts

@@ -64,3 +64,17 @@ test("StringStream split can stream with only one split value", async (t) => {
 
     t.deepEqual(result, ["", ""]);
 });
+
+test("StringStream can split chunks by given regexp #1", async (t) => {
+    const stringStream = StringStream.from(["foo1bar", "baz111bax", "123", "345", "011", "201"]);
+    const result = await stringStream.split(/1+/).toArray();
+
+    t.deepEqual(result, ["foo", "barbaz", "bax", "233450", "20", ""]);
+});
+
+test("StringStream can split chunks by given regexp #2", async (t) => {
+    const stringStream = StringStream.from(["foo1bar", "baz111bax", "123", "345", "011", "201"]);
+    const result = await stringStream.split(/1{1,2}/).toArray();
+
+    t.deepEqual(result, ["foo", "barbaz", "", "bax", "233450", "20", ""]);
+});