isIdentity = (matrix) => (
  matrix[0] === 1 && matrix[1] === 0 && matrix[2] === 0 && matrix[3] === 0 &&
  matrix[4] === 0 && matrix[5] === 1 && matrix[6] === 0 && matrix[7] === 0 &&
  matrix[8] === 0 && matrix[9] === 0 && matrix[10] === 1 && matrix[11] === 0 &&
  matrix[12] === 0 && matrix[13] === 0 && matrix[14] === 0 && matrix[15] === 1
)
Determine whether the given matrix is the identity transform.
This is equivalent to (but much faster than):

    mat4.equals(mat4.create(), matrix)

@param {mat4} matrix - the matrix
@returns {Boolean} true if matrix is the identity transform
@alias module:modeling/maths/mat4.isIdentity
@example
if (mat4.isIdentity(mymatrix)) ...