enso/tools/ci/nightly/extract-release-notes.js

const fs = require('fs')

const inputPath = process.argv[2]
const outputPath = process.argv[3]

console.log('Extracting release notes from ' + inputPath + ' to ' + outputPath)

/** Returns the part of the text until the second top-level heading (exclusive)
 * in Markdown formatting.
 */
function cutFirstSection(content) {
    const nightlySectionRegex = /^# Enso Next$/gm
    function findNightlySectionStart(text) {
        return text.search(nightlySectionRegex)
    }
    const regularSectionRegex = /^# Enso .*? \(\d\d\d\d-\d\d-\d\d\)$/gm
    function findFirstRegularSectionStart(text) {
        return text.search(regularSectionRegex)
    }
    function findNewline(text) {
        return text.indexOf('\n')
    }

    const firstHeading = findNightlySectionStart(content)
    if (firstHeading < 0) {
        throw 'Could not find the nightly section, matching ' + nightlySectionRegex
    }

    const restOffset = firstHeading + 2
    const newLineOffset = findNewline(content.substring(restOffset))
    if (newLineOffset < 0) {
        throw 'No content after the section heading'
    }
    const restStart = restOffset + newLineOffset + 1

    const rest = content.substring(restStart)
    const secondHeading = findFirstRegularSectionStart(rest)
    if (secondHeading < 0) {
        throw 'Could not find the first released section, matching' + regularSectionRegex
    }

    const firstSectionContent = rest.substring(0, secondHeading)
    return firstSectionContent
}

try {
    const content = fs.readFileSync(inputPath, { encoding: 'utf-8' })
    const nightlyPart = cutFirstSection(content)
    fs.writeFileSync(outputPath, nightlyPart)

    console.log('Created ' + outputPath + ' with the following content:')
    console.log(nightlyPart)
} catch (exc) {
    console.error(exc)
    process.exit(1)
}