analyze_pubg.js

var fs = require("fs");
var inputData = JSON.parse(fs.readFileSync('data.json', 'utf-8'));

function round(value, decimals) {
  return Number(Math.round(value+'e'+decimals)+'e-'+decimals);
}

var level3Types = [
    "Level 3 Military Vest",
    "Level 3 Helmet",
    "Level 3 Backpack"
];

var sniperTypes = [
    "SKS",
    "M24",
    "AWM",
    "Kar98",
    "VSS"
];

function numberOfCratesWithTypes(data, types) {
    return data.filter((package) => {
        return types.reduce((hasItem, item) => hasItem || item in package, false);
    }).length;
}

function totalNumberOfTypes(data, types) {

    return data.reduce((totalItems, package) => {
        return totalItems + types.reduce((itemsInPackage, item) => {
            return itemsInPackage + (item in package ? package[item] : 0);
        }, 0);
    }, 0);
}

function chanceOfCrateWithTypes(data, types) {
    return numberOfCratesWithTypes(data, types) / data.length;
}

function numberOfCratesWithTwoSameTypes(data, types) {
    return data.filter((package) => {
        return (types.reduce((itemsInPackage, item) => itemsInPackage + (item in package ? package[item] : 0), 0)) > 2;
    }).length;
}

function numberOfCratesWithTwoDifferentTypes(data, types1, types2) {
    return data.filter(package => {
        var containsType1 = types1.reduce((hasItem, item) => hasItem || item in package, false);
        var containsType2 = types2.reduce((hasItem, item) => hasItem || item in package, false);
        return containsType1 && containsType2;
    }).length;
}

function numberOfCratesWithTypes1NotTypes2(data, types1, types2) {
    
    return data.filter(package => {
        var containsType1 = types1.reduce((hasItem, item) => hasItem || item in package, false);
        var containsType2 = types2.reduce((hasItem, item) => hasItem || item in package, false);
        return containsType1 && !containsType2;
    }).length;
}

function numberOfCratesWithoutTypes(data, types) {
    return data.filter(package => {
        return !(types.reduce((hasItem, item) => hasItem || item in package, false));
    }).length;
}

function chanceOfCrateWithTypes1GivenTypes2(data, types1, types2) {
    return numberOfCratesWithTwoDifferentTypes(data,types1,types2) / numberOfCratesWithTypes(data,types2);
}

function chanceOfCrateWithTypes1NotTypes2(data, types1, types2) {
    return numberOfCratesWithTypes1NotTypes2(data,types1,types2) / numberOfCratesWithoutTypes(data,types2);
}

console.log("Number of crates with one or more level 3 gear pieces: " + round(numberOfCratesWithTypes(inputData, level3Types),2));
console.log("Number of crates with two or more level 3 gear pieces: " + round(numberOfCratesWithTwoSameTypes(inputData, level3Types),2));

console.log("");
console.log("Number of crates with snipers: " + round(numberOfCratesWithTypes(inputData, sniperTypes),2));
console.log("Total number of snipers: " + round(totalNumberOfTypes(inputData, sniperTypes),2));
console.log("Chance to find crate with sniper weapon: " + round(chanceOfCrateWithTypes(inputData, sniperTypes),2));

console.log("");
console.log("Number of crates with 15x scopes: " + round(numberOfCratesWithTypes(inputData, ["15X Scope"]),2));
console.log("Total number of 15x scopes: " + round(totalNumberOfTypes(inputData, ["15X Scope"]),2));
console.log("Chance to find 15x scope: " + round(chanceOfCrateWithTypes(inputData, ["15X Scope"]),2));

console.log("");
console.log("Chance to find 15x scope when there is a sniper in the crate: " + round(chanceOfCrateWithTypes1GivenTypes2(inputData, ["15X Scope"], sniperTypes),2));
console.log("Chance to find 15x scope when there is no sniper in the crate: " + round(chanceOfCrateWithTypes1NotTypes2(inputData, ["15X Scope"], sniperTypes), 2));

/* ================ OUTPUTS =================

Number of crates with one or more level 3 gear pieces: 56
Number of crates with two or more level 3 gear pieces: 0

Number of crates with snipers: 62
Total number of snipers: 62
Chance to find crate with sniper weapon: 0.61

Number of crates with 15x scopes: 6
Total number of 15x scopes: 6
Chance to find 15x scope: 0.06

Chance to find 15x scope when there is a sniper in the crate: 0.06
Chance to find 15x scope when there is no sniper in the crate: 0.05

   ================ OUTPUTS ================== */