This code for third person camera follow

Help & Support
1 
pc.script.create('pc:third_person_camera', function (context) {

    var attr = {
        DISTANCE: 1.5,
        ENTITY_NAME: 'camera target',
        X_SCALE: 0.1,
        Y_SCALE: 0.1,
        X_LIMIT: 0.15,
        Y_LIMIT: 0.15,
        MIN_PITCH: -0.1,
        MAX_PITCH: 0.1
    };

    var ThirdPersonCamera = function (entity) {
        this.entity = entity;

        // euler angles
        this.x = attr.MIN_PITCH;
        this.y = Math.PI;

        this.lasth = 0;
        this.lastv = 0;
    };

    ThirdPersonCamera.prototype = {
        initialize: function () {
            this.targetEntity = context.root.findByName(attr.ENTITY_NAME);
        },

        update: function (dt) {
            if (!context.controller) {
                return;
            }

            var lookx = context.controller.getAxis('lookx');
            var looky = context.controller.getAxis('looky');

            var x = lookx * lookx;
            var y = looky * looky;

            var xSign = lookx > 0 ? 1 : -1;
            var ySign = looky > 0 ? 1 : -1;

            x = xSign * x * attr.X_SCALE;
            y = ySign * y * attr.Y_SCALE;

            var dh = pc.math.clamp(x, -attr.X_LIMIT, attr.X_LIMIT);
            var dv = pc.math.clamp(y, -attr.Y_LIMIT, attr.Y_LIMIT);

            dh = this.lerp(this.lasth, dh, 0.5);
            dv = this.lerp(this.lastv, dv, 0.5);

            this.x += dv;
            this.x = pc.math.clamp(this.x, attr.MIN_PITCH, attr.MAX_PITCH);

            this.y -= dh;
            if (this.y < 0) {
                this.y += Math.PI * 2;
            } else if (this.y > Math.PI * 2) {
                this.y -= Math.PI * 2;
            }

            this.lasth = dh;
            this.lastv = dv;

            this.entity.setPosition(this.targetEntity.getPosition());
            this.entity.setEulerAngles(this.x * pc.math.RAD_TO_DEG, this.y * pc.math.RAD_TO_DEG, 0);
            this.entity.translateLocal(0, 0, attr.DISTANCE);
        },

        lerp: function (value, target, t) {
            return value + (target - value) * t;
        },
    };

    return ThirdPersonCamera;
});
2

Why are you posting this? I would recommend against using the old script format that you have here. Instead, I strongly advise you use the current script format outlined here:

https://developer.playcanvas.com/en/user-manual/scripting/anatomy/