您可以使用以下defaultColDef函数实现差异突出显示：

defaultColDef = {
    cellStyle: function(params) {
        const rowIndex = params.node.rowIndex;
        const columnId = params.colDef.field;

        const previousRowIndex = rowIndex - 1;
        if(params.api.getDisplayedRowAtIndex(previousRowIndex) === undefined){
          return { 'background-color': null};
        }

        const currentValue = params.value;
        const previousValue = params.api.getDisplayedRowAtIndex(previousRowIndex).data[columnId];

        if (currentValue !== previousValue) {
          return { 'background-color': 'lightblue' };
        }

        return { 'background-color': null};
      }
  }

下面是代码：https://stackblitz.com/edit/ag-grid-diff-highlighting