JSFiddle - React, Tailwind, and code Playground

JavaScript

var data_consumed_dollars = [[1356998400000, 0.030380282850000006], [1357002000000, 0.0395505288], [1357005600000, 0.04084797307500001]];

var data_solargeneration_dollars = [[1356998400000, 0.030972182850000006], [1357178400000, 0], [1357182000000, 0], [1357185600000, 0], [1357189200000, 0], [1356998400000, 0.030380282850000006]];

var matched_elements = [];
    
    for(var x = 0; x < data_consumed_dollars.length; x++){
        for(var y = 0; y < data_solargeneration_dollars.length; y++){
          if(data_consumed_dollars[x][0] == data_solargeneration_dollars[y][0] && data_consumed_dollars[x][1] == data_solargeneration_dollars[y][1]){
      matched_elements.push([data_consumed_dollars[x][0],data_consumed_dollars[x][1]]);
          }
        }
      }
console.log(matched_elements);