Navigator frozen!

Hello everybody, my build was going quite ok, but one error in the unifiedSpawn script is frozen the entire playcanvas, and i have to close all the windows and restart playcanvas everytime. I have nailed down the problem to be in the unfiedSpanner script, in the launchWave function at the very begning. If I take those lignes out, I can launch, I have no idea of what is goint on here is the project : https://playcanvas.com/project/1332209/overview/jeu-des-relatifs-222
here are the Devil’s lines :

this.isSpawning = true;
this.spawnedShips = [ ];
    let a = pc.math.random(-16, 16) | 0;
    let b = pc.math.random(-16, 16) | 0;
    let result;
    let valid = false;
    const types = ['addition_meme', 'addition_oppose', 'soustraction_meme', 'soustraction_oppose'];
    const missionType = types[Math.floor(Math.random() * types.length)];

    if (a !== 0 && b !== 0) {
        const sameSign = (a * b > 0);
        const expectedSame = missionType.endsWith('meme');
        const opAdd = missionType.startsWith('addition');

        if (sameSign === expectedSame) {
            result = opAdd ? a + b : a - b;
            if (result >= -31 && result <= 31) {
                valid = true;
            }
        }
    }

what do you think about that?

Forget about my topic, I have given to much credit to AI to solve a probem, that I have solved in fex minutes with a fresh mind. Thet were too any waves of ship. launched for several scripts, and the ships with rigid bodies and collision bow where spawning at the same place, after a while I supposed the physics engine collapsed. I have removed useless launchwaves, and every thing works perfect. Thanks anyway for you help