Vera URL generator.

vera-urls.js

const BASE_URL = 'https://arresttrends.vera.org/';
const MAX_DEPTH = 2;

const PARAMS = {
  AMOUNT: {
    name: 'amount',
    values: ['some', 'all']
  },
  DATASET: {
    name: 'dataset',
    values: ['police', 'fbi']
  },
  ESTIMATED: {
    name: 'estimated',
    values: [0, 1]
  },
  LOCATION: {
    name: 'location',
    values: [2, 3, 4, 5]
  },
  OFFENSE_1: {
    name: 'offense',
    values: ['part1', 'violent', 'property', '01', '02', '03', '04', '05', '06', '07']
  },
  OFFENSE_ALL: {
    name: 'offense',
    values: [
      'part1', 'part2', 'violent', 'property',
      '01', '02', '03', '04', '05', '06', '07', '08', '09', '10',
      '11', '12', '13', '14', '15', '16', '17', '18', '19', '20',
      '21', '22', '23', '24', '25', '26', '27', '28', '29',
    ]
  },
  REPORTED: {
    name: 'reported',
    values: ['clearance', 'race', 'ethnicity']
  },
  START_1964_2016: {
    name: 'start',
    values: getRange(1964, 2016)
  },
  START_1980_2016: {
    name: 'start',
    values: getRange(1980, 2016)
  },
  START_1993_2016: {
    name: 'start',
    values: getRange(1993, 2016)
  },
  TYPE: {
    name: 'type',
    values: ['national', 'region', 'state', 'county']
  },
  UNIT: {
    name: 'unit',
    values: ['rate']
  },
  YEAR_1964_2016: {
    name: 'year',
    values: getRange(1964, 2016)
  },
  YEAR_1980_2016: {
    name: 'year',
    values: getRange(1980, 2016)
  },
  YEAR_1993_2016: {
    name: 'year',
    values: getRange(1993, 2016)
  },
};

const PAGES = {
  'arrests':  [
    PARAMS.ESTIMATED,
    PARAMS.LOCATION,
    PARAMS.OFFENSE_ALL,
    PARAMS.START_1980_2016,
    PARAMS.TYPE,
    PARAMS.UNIT,
    PARAMS.YEAR_1980_2016,
  ],
  'demographics': [
    PARAMS.ESTIMATED,
    PARAMS.LOCATION,
    PARAMS.OFFENSE_ALL,
    PARAMS.START_1980_2016,
    PARAMS.TYPE,
    PARAMS.UNIT,
    PARAMS.YEAR_1980_2016,
  ],
  'clearance-rates': [
    PARAMS.LOCATION,
    PARAMS.OFFENSE_1,
    PARAMS.START_1964_2016,
    PARAMS.TYPE,
    PARAMS.YEAR_1964_2016,
  ],
  'victimizations': [
    PARAMS.DATASET,
    PARAMS.LOCATION,
    PARAMS.OFFENSE_1,
    PARAMS.START_1993_2016,
    PARAMS.TYPE,
    PARAMS.UNIT,
    PARAMS.YEAR_1993_2016,
  ],
  'data-reported': [
    PARAMS.AMOUNT,
    PARAMS.LOCATION,
    PARAMS.REPORTED,
    PARAMS.START_1980_2016,
    PARAMS.YEAR_1980_2016,
  ],
};

function getRange(start, end) {
  var ans = [];
  for (let i = start; i <= end; i++) {
      ans.push(i);
  }
  return ans;
}

function generateURLs(prefix, params, urlFunc, maxDepth, depth = 0, concat = '?') {
  // BAIL -- over depth
  if (maxDepth != null && depth > maxDepth) {
    return;
  }

  if (params.length === 0) {
    urlFunc(prefix);
    return;
  }

  let headParam = params[0];
  let tailParams = params.slice(1);

  generateURLs(prefix, tailParams, urlFunc, maxDepth, depth, concat);

  headParam.values.forEach(value => {
    generateURLs(prefix + concat + headParam.name + '=' + value, tailParams, urlFunc, maxDepth, depth + 1, '&');
  });
}

function isValid(url) {
  url = new URL(url);
  let start = url.searchParams.get('start');

  if (start) {
    let year = url.searchParams.get('year');

    // FAIL -- start without year (UI disallows)
    if (!year) {
      return false;
    }

    // FAIL -- start > year (UI disallows)
    if (parseInt(start) > parseInt(year)) {
      return false;
    }
  }

  return true;
}

function main() {
  let count = 0;
  let urlFunc = function(url) {
    if (isValid(url)) {
      console.debug(url);
      count++;
    }
  }

  for (const path in PAGES) {
    generateURLs(BASE_URL + path, PAGES[path], urlFunc, MAX_DEPTH);
  }

  console.debug(count);
}

main();