node-benchmark

Plain Object Vs Class Vs Array

obj means plain javascript object such as { Xx: 1, Xy: 0, Yx: 0, Yy: 1, Tx: 0, Ty: 0 }

cls1 is for a class with field declarations without default value

class XfCls1 {
    Xx;
    Xy;
    Yx;
    Yy;
    Tx;
    Ty;
    constructor(Xx, Xy, Yx, Yy, Tx, Ty) {
        this.Xx = Xx;
        this.Xy = Xy;
        this.Yx = Yx;
        this.Yy = Yy;
        this.Tx = Tx;
        this.Ty = Ty;
    }
}

cls2 is for a class without field declarations such as

class XfCls2 {
    constructor(Xx, Xy, Yx, Yy, Tx, Ty) {
        this.Xx = Xx;
        this.Xy = Xy;
        this.Yx = Yx;
        this.Yy = Yy;
        this.Tx = Tx;
        this.Ty = Ty;
    }
}

cls3 is for a class with field declarations and with default values

class XfCls3 {
    Xx = -0;
    Xy = -0;
    Yx = -0;
    Yy = -0;
    Tx = -0;
    Ty = -0;
    constructor(Xx, Xy, Yx, Yy, Tx, Ty) {
        this.Xx = Xx;
        this.Xy = Xy;
        this.Yx = Yx;
        this.Yy = Yy;
        this.Tx = Tx;
        this.Ty = Ty;
    }
}

arr1 stands for a number array of length 6 such as [1, 0, 0, 1, 0, 0]. In this case V8 chooses to use PACKED_SMI_ELEMENTS or PACKED_DOUBLE_ELEMENTS

arr2 stands for a number array of length 6 in which all the values are forced to be float64 at creation time (PACKED_DOUBLE_ELEMENTS) [-0 + 1, -0, -0, -0 + 1, -0, -0]

arr3/arr4 are the same as arr1/arr2 but instead of using array destructuring to access its elements (const [ Xx, Xy, Yx, Yy, Tx, Ty ] = arr), we acces them one by one using the index : const Xx = arr[0], const Xy = arr[1], ...

ReadnAndWrite Vs ReadOnly

By default the operation performed on the Xfs reads the values of 2 Xfs and write in the 3rd Xf. It is a read and write (rw) operation. To compare performance when only read operations are made on the xf, the option ro can be added as a second argument.

How to run

node xf6.js obj rw or node xf6.js obj ro or node xf6.js cls1 rw or node xf6.js cls1 ro...

run them all

yarn run-all

results

objType	rw time (ms)	ro time (ms)
obj	3816	3816
cls1	12982	2696
cls2	2760	3314
cls3	2684	2899
arr1	15601	17121
arr2	5415	8152
arr3	2237	2111
arr4	2219	2055

profiling

node --cpu-prof --cpu-prof-name cls1_rw.cpuprofile xf6.js cls1 rw and open it with Chrome Dev Tools