1. @DomName('WebGL2RenderingContext.stencilOpSeparate')
  2. @DocsEditable()
  3. @Experimental()
void stencilOpSeparate(int face, int fail, int zfail, int zpass)

Source 

@DomName('WebGL2RenderingContext.stencilOpSeparate')
@DocsEditable()
@Experimental() // untriaged
void stencilOpSeparate(int face, int fail, int zfail, int zpass) =>
    _blink.BlinkWebGL2RenderingContext.instance
        .stencilOpSeparate_Callback_4_(this, face, fail, zfail, zpass);