Add alternative fp implementation

Author: tshemsedinov

JavaScript/2-functional-alternative.js

@@ -0,0 +1,32 @@
+'use strict';
+
+const fs = require('fs');
+
+const proportion = (max, val) => Math.round(val * 100 / max);
+const compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x);
+
+const densityCol = 3;
+const cellWidth = [18, 10, 8, 8, 18, 6];
+
+const renderTable = table => table
+ .map(row => row
+ .map((cell, i) => cell
+ .toString()[(i ? 'padStart' : 'padEnd')](cellWidth[i]))
+ .join(''))
+ .join('\n');
+
+const calcProportion = table => (
+ table.sort((row1, row2) => (row2[densityCol] - row1[densityCol])),
+ table.map(row => (
+ row.push(proportion(table[0][densityCol], row[densityCol])), row
+ ))
+);
+
+const getDataset = file => fs.readFileSync(file).toString()
+ .split('\n')
+ .filter((s, i) => i && s)
+ .map(line => line.split(','));
+
+const main = compose(getDataset, calcProportion, renderTable);
+
+console.log(main('./cities.dat'));