table42

Table For Two -- Two-dimensional HashMap/Table datastructure

A Table is like a Map, except you use key-pairs to access your data. Empty fields in the Table return a default value. Example:

const Table = require('table42');
let timesheet = new Table();

timesheet.set('Jan', 1, 8.0);
timesheet.set('Jan', 2, 4.5);
timesheet.set('Feb', 1, 7.0);

timesheet.get('Jan', 1); // => 8
timesheet.get('Jan', 2); // => 4.5
timesheet.get('Feb', 1); // => 7
timesheet.get('Feb', 2); // => 0 // default

Run tests with npm test. This is just the byproduct of an other project of mine. Feel free to open issues or send PRs on GitHub. There are probably a million things that still need some love, but the basic functionality is there.

Note that this was designed for string keys and numerical values. Other types may or may not work.

Guava has a similar datastructure.

Features

Sum values if record exists:

timesheet.set('Jan', 1, 8.0);
timesheet.get('Jan', 1); // => 8
timesheet.setOrAdd('Jan', 1, 2.0);
timesheet.get('Jan', 1); // => 10

CSV Export:

timesheet.toCSV(); // => ',1,2\nJan,8,4.5\nFeb,7,0\n'

Parse CSV:

timesheet = Table.parse(',1,2\nJan,8,4.5\nFeb,7,0\n');
timesheet.get('Jan', 1); // => 8
timesheet.get('Jan', 2); // => 4.5
timesheet.get('Feb', 1); // => 7
timesheet.get('Feb', 2); // => 0

Parse JSON:

let data = [
  {"r": "Jan", "1": 8, "2": 4.5},
  {"r": "Feb", "1": 7, "2": 0}
];
timesheet = Table.parseJSON(JSON.stringify(data), 'r');
timesheet.get('Jan', "1"); // => 8
timesheet.get('Jan', "2"); // => 4.5
timesheet.get('Feb', "1"); // => 7
timesheet.get('Feb', "2"); // => 0

Sort rows of Table in place according to a row reduce function:

table.set('r2', 'c1', 2);
table.set('r2', 'c2', 2);
table.set('r3', 'c1', 3);
table.set('r3', 'c2', 3);
table.set('r1', 'c1', 1);
table.set('r1', 'c2', 1);
table._rows; // => ['r2', 'r3', 'r1'];
function summarizeRow(row) {
  return row.reduce((acc, val) => acc + val, 0);
}
table.sortRowsDescending(summarizeRow);
table._rows; // => ['r3', 'r2', 'r1'];