generator.ts

class User {
    public birthDate: Date;

    public constructor(
        public readonly firstname: string = 'Douggie',
        public readonly lastname: string = 'Dougs',
    ) {
        const birthYear = Math.floor((Math.random() * 50) + 1970)
        this.birthDate = new Date(birthYear, 1, 1);
    }

    get age(): number {
        return new Date().getFullYear() - this.birthDate.getFullYear()
    }
}

function get10MUsers(): User[] {
    const users: User[] = [];

    for (let i = 0; i < 10_000_000 ; ++i) {
        users.push(new User);
    }

    return users;
}

// for (const user of get10MUsers()) {
//     console.log(`${user.firstname} ${user.lastname} has ${user.age}`);
    // FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory
    // <--- Last few GCs --->
    // oc[9121:0x103dd2000]    40912 ms: Mark-sweep 2048.9 (2053.4) -> 2048.4 (2054.1) MB, 2122.9 / 0.0 ms  (+ 94.9 ms in 22 steps since start of marking, biggest step 5.4 ms, walltime since start of marking 2222 ms) (average mu = 0.098, current mu = 0.002) alloca[9121:0x103dd2000]    42972 ms: Mark-sweep 2049.7 (2054.1) -> 2049.3 (2054.9) MB, 1956.9 / 0.0 ms  (+ 98.2 ms in 22 steps since start of marking, biggest step 5.3 ms, walltime since start of marking 2059 ms) (average mu = 0.052, current mu = 0.002) alloca
// }

function* get10MUsersGenerator(): Generator<User> {
    for (let i = 0; i < 10_000_000 ; ++i) {
        yield new User;
    }
    return;
}

// ts-node --compiler-options '{"downlevelIteration": true}'  api/generator.t~
for (const user of get10MUsersGenerator()) {
    console.log(`${user.firstname} ${user.lastname} has ${user.age}`);
}