collapse unchanged not working

I am trying to build 3 way merge in vue JS to compare JSON files, using codemirror 6 (“@codemirror/lang-html”: “^6.4.8”,
@codemirror/lang-xml”: “^6.1.0”,
@codemirror/merge”: “^6.6.1”,), i need collapse unchanged code in the merge editor

I am using the below code, but the unchanged code is not collapsing.

please can someone help?

mounted() {
this.mergeView = CodeMirror.MergeView(this.$refs.mergeView, {
value: this.baseSide,
origLeft: this.leftSide,
origRight: this.rightSide,
theme: “elegant”,
height: “auto”,
mode: “javascript”,
lineNumbers: true,
indentWithTabs: false,
tabSize: 2,
matchBrackets: true,
cursorHeight: 0,
styleActiveLine: true,
collapseUnchanged: {margin: 5, minSize: 2},
highlightDifferences: true,
connect: “align”,


Please can i have a reply for this?