todo.txt extension - count finished tasks by project references

projectcount.js

#!/usr/bin/env node
const fs = require('fs')
const path = require('path')
const readline = require('readline')
const todo_dir = process.env.TODO_DIR
// TODO we could make this optionally count todo.txt too e.g. with a CLI flag
const done_file = path.join(todo_dir, 'done.txt')
const projregex = /(\+[A-Za-z0-9]+)(\s|$)/g
const ctxregex = /(@[A-Za-z0-9]+)(\s|$)/g
let counts = {}

if (process.argv.includes('usage')) {
    console.log(
`    projectcount
      Counts the number of times each project ("+project") was mentioned in a
      completed task i.e. in done.txt.
      -c, --ctx, --context flag: count @contexts instead of +projects.`)
    process.exit(0)
}

let regex = null
if (process.argv.includes('-c') || process.argv.includes('--ctx') || process.argv.includes('--context')) {
    regex = ctxregex
} else {
    regex = projregex
}

const rl = readline.createInterface({
    input: fs.createReadStream(done_file),
    crlfDelay: Infinity // treate CRLF as line ending
})

rl.on('line', (line) => {
    let matches = line.match(regex)
    matches && matches.forEach(match => {
        let project = match.trim().substring(1).toLowerCase()
        counts.hasOwnProperty(project) ? counts[project]++ : counts[project] = 1
    })
}).on('close', () => {
    // we want column width to be _at least_ the longest project name + 1
    let width = Object.keys(counts).reduce((acc, val) => {
        if (acc > val.length) return acc
        return val.length
    }, 0) + 1
    console.log(`${'Project'.padEnd(width)} Tasks`)
    // Object.entries returns an array of [key, value] arrays
    Object.entries(counts).sort((a, b) => {
        return b[1] - a[1]
    }).forEach(p => {
        console.log(`${p[0].padEnd(width)} ${p[1]}`)
    })
})