LWC - Iterate through rows of lightning datatable using javascript

Question

Are we able to iterate through the rows of a lighting datatable and query each columns value in Javascript?

Like this, but for a lightning datatable: https://stackoverflow.com/questions/3065342/how-do-i-iterate-through-table-rows-and-cells-in-javascript

I would imagine it's something like below, but this doesn't work obviously.

var rows = this.template.querySelector('my-custom-datatable');
for (var i = 0, row; row = table.rows[i]; i++) {
   //iterate through rows
   //rows would be accessed using the "row" variable assigned in the for loop
   for (var j = 0, col; col = row.cells[j]; j++) {
     //iterate through columns
     //columns would be accessed using the "col" variable assigned in the for loop
   }  
}

Answer 1

Another way would be to get the lightning-datatable using template.querySelector and then access the rows attribute

 iterateOverTable(event){        
        var table = this.template.querySelector('lightning-datatable');
        var rows = table.data;
        rows.forEach(function(element){
            console.log(element.name);
        });

    }

Playground Link : https://developer.salesforce.com/docs/component-library/tools/playground/Nh9CElBEE/1/edit

Answer 2

You can manipulate the returned data from your apex controller and then point that property as your edited data to your lightning-datatable.

This is for aura but the idea is the same:

        action.setCallback(this, $A.getCallback(function (response) {
        let state = response.getState();
        if (state === "SUCCESS") {
            let resultData = response.getReturnValue();
            if (resultData !== null) {

                resultData.forEach(function (record) {
                    if (typeof record.Id != 'undefined') {
                        if (record.IsActive) {
                            record.displayIconName = 'utility:check';
                            record.showClass = 'greencolor'
                        } else {
                            record.displayIconName = 'utility:close';
                            record.displayIconName = 'redcolor';
                        }
                    }
                });

                component.set("v.data", resultData);