1class Tunjangan {
2	kids = 0
3	age = {}
4	balita = 0
5	anak = 0
6	remaja = 0
7	sallary = 0
8	sum = 0
9
10	constructor(sallary, kids, age) {
11		this.sallary = sallary
12		this.kids = kids
13		this.age = age
14	}
15
16	validation() {
17		if (this.age.firstKids > 15 || this.age.secondKids > 15) {
18			return Promise.reject(new Error('Maximum age 15 years old'))
19		} else if (this.age.firstKids < 1) {
20			return Promise.reject(new Error('Minimum age 1 years old'))
21		} else if (this.kids > 2) {
22			return Promise.reject(new Error('Maximum 2 children'))
23		} else if (this.kids < 1) {
24			return Promise.reject(new Error('Minimum 1 children'))
25		} else if (this.kids == 1) {
26			this.age.secondKids = 0
27		}
28
29		return true
30	}
31
32	percentageBalita() {
33		const betweenAge = [1, 2, 3, 4, 5]
34		if (betweenAge.includes(this.age.firstKids) || betweenAge.includes(this.age.secondKids)) {
35			betweenAge.includes(this.age.firstKids) && betweenAge.includes(this.age.secondKids)
36				? (this.balita = 5 + 5)
37				: (this.balita = 5)
38		}
39		return this.balita
40	}
41
42	percentageAnak() {
43		const betweenAge = [6, 7, 8, 9, 10]
44		if (betweenAge.includes(this.age.firstKids) || betweenAge.includes(this.age.secondKids)) {
45			betweenAge.includes(this.age.firstKids) && betweenAge.includes(this.age.secondKids) ? (this.anak = 7 + 7) : (this.anak = 7)
46		}
47		return this.anak
48	}
49
50	percentageRemaja() {
51		const betweenAge = [11, 12, 13, 14, 15]
52		if (betweenAge.includes(this.age.firstKids) || betweenAge.includes(this.age.secondKids)) {
53			betweenAge.includes(this.age.firstKids) && betweenAge.includes(this.age.secondKids)
54				? (this.remaja = 10 + 10)
55				: (this.remaja = 10)
56		}
57		return this.remaja
58	}
59
60	percentageAge() {
61		if (typeof this.validation() === 'boolean') {
62			this.percentageBalita()
63			this.percentageAnak()
64			this.percentageRemaja()
65		}
66		return { balita: this.balita, anak: this.anak, remaja: this.remaja }
67	}
68
69	sumTunjanganKids() {
70		const balita = Math.floor((this.percentageAge().balita / 100) * this.sallary)
71		const anak = Math.floor((this.percentageAge().anak / 100) * this.sallary)
72		const remaja = Math.floor((this.percentageAge().remaja / 100) * this.sallary)
73		return { balita, anak, remaja }
74	}
75
76	totalSalaryPlusKids() {
77		const balita = this.sumTunjanganKids().balita
78		const anak = this.sumTunjanganKids().anak
79		const remaja = this.sumTunjanganKids().remaja
80		return this.sallary + balita + anak + remaja
81	}
82
83	reportingTunjangan() {
84		const subTotal = result.totalSalaryPlusKids()
85		const before = `${new Intl.NumberFormat('en-ID', { currency: 'IDR' }).format(this.sallary)}`
86		const after = `${new Intl.NumberFormat('en-ID', { currency: 'IDR' }).format(subTotal)}`
87		return {
88			sallary: {
89				before: `Your current sallary RP.${before}`,
90				after: `Your current sallary + allowence for kids RP.${after}`
91			}
92		}
93	}
94}
95
96const result = new Tunjangan(3500000, 1, { firstKids: 1, secondKids: 0 })
97console.log(result.reportingTunjangan())

1Typically, JavaScript is related to 
2Front End Web Development.
3The typical UK hourly rate is approx £12.20
4for a Web Developer.