Creates findAndReplaceOffset funtion

Creates a function to find the last offset and
remove it if repeated

app/assets/javascripts/jobs/store/utils.js

@@ -55,6 +55,39 @@ export const logLinesParser = (lines = [], lineNumberStart) =>
     return acc;
   }, []);
 
+/**
+ * Finds the repeated offset, removes the old one
+ *
+ * Returns a new object with the updated log without
+ * the repeated offset and the last line number.
+ *
+ * @param Array newLog
+ * @param Array oldParsed
+ * @returns Object
+ *
+ */
+export const findOffsetAndRemove = (newLog, oldParsed) => {
+  const cloneOldLog = [...oldParsed];
+  const lastIndex = cloneOldLog.length - 1;
+  const last = cloneOldLog[lastIndex];
+
+  const firstNew = newLog[0];
+  const parsed = {};
+
+  if (last.offset === firstNew.offset || (last.line && last.line.offset === firstNew.offset)) {
+    cloneOldLog.splice(lastIndex);
+    parsed.lastLine = last.lineNumber;
+  } else if (last.lines && last.lines.length) {
+    const lastNestedIndex = last.lines.length - 1;
+    const lastNested = last.lines[lastNestedIndex];
+    if (lastNested.offset === firstNew.offset) {
+      last.lines.splice(lastNestedIndex);
+      parsed.lastLine = lastNested.lineNumber;
+    }
+  }
+  return cloneOldLog;
+};
+
 /**
  * When the trace is not complete, backend may send the last received line
  * in the new response.

spec/frontend/jobs/store/utils_spec.js

@@ -3,6 +3,7 @@ import {
   updateIncrementalTrace,
   parseHeaderLine,
   parseLine,
+  findOffsetAndRemove,
 } from '~/jobs/store/utils';
 import {
   utilsMockData,
@@ -83,6 +84,59 @@ describe('Jobs Store Utils', () => {
     });
   });
 
+  describe('findOffsetAndRemove', () => {
+    describe('when last item is header', () => {
+      describe('when last item matches the offset', () => {
+        it('returns an object with the item removed and the lastLine', () => {
+          const newData = [{ offset: 10, content: [{ text: 'foobar' }] }];
+          const existingLog = [{ line: { content: [{ text: 'bar' }], offset: 10, lineNumber: 1 } }];
+          const result = findOffsetAndRemove(newData, existingLog);
+          expect(result).toEqual([]);
+        });
+      });
+    });
+
+    describe('when last item is a regular line', () => {
+      describe('and matches the offset', () => {
+        it('returns an object with the item removed and the lastLine', () => {
+          const newData = [{ offset: 10, content: [{ text: 'foobar' }] }];
+          const existingLog = [{ content: [{ text: 'bar' }], offset: 10, lineNumber: 1 }];
+          const result = findOffsetAndRemove(newData, existingLog);
+          expect(result).toEqual([]);
+        });
+      });
+    });
+
+    describe('when last collaspible line item matches the offset', () => {
+      it('returns an object with the last nested line item removed and the lastLine', () => {
+        const newData = [{ offset: 101, content: [{ text: 'foobar' }] }];
+        const existingLog = [
+          {
+            isHeader: true,
+            isClosed: true,
+            lines: [{ offset: 101, content: [{ text: 'foobar' }], lineNumber: 2 }],
+            line: {
+              offset: 10,
+              lineNumber: 1,
+              section_duration: '10:00',
+            },
+          },
+        ];
+        const result = findOffsetAndRemove(newData, existingLog);
+        expect(result[0].lines).toEqual([]);
+      });
+    });
+
+    describe('when it does not match the offset', () => {
+      it('returns an object with the complete old log and the last line number', () => {
+        const newData = [{ offset: 101, content: [{ text: 'foobar' }] }];
+        const existingLog = [{ line: { content: [{ text: 'bar' }], offset: 10, lineNumber: 1 } }];
+        const result = findOffsetAndRemove(newData, existingLog);
+        expect(result).toEqual(existingLog);
+      });
+    });
+  });
+
   describe('updateIncrementalTrace', () => {
     describe('without repeated section', () => {
       it('concats and parses both arrays', () => {