glslify did not interpret the string.

I install glslify 6.0.1 in my project with npm.

import the glslify file in my js file with
`var glslify = require('glslify');`

And use it as
_copyShader = new THREE.RawShaderMaterial({
uniforms: {
resolution: { type: 'v2', value: new THREE.Vector2( TEXTURE_WIDTH, TEXTURE_HEIGHT ) },
texture: { type: 't', value: undef }
},
vertexShader: rawShaderPrefix + shaderParse(glslify('../glsl/quad.vert')),
fragmentShader: rawShaderPrefix + shaderParse(glslify('../glsl/through.frag'))
});

But got syntax error that said unexpected "." on my line 2.
I think it is because glslify did not interpret the string and get the file, just add the string to the shader. Is there a way that I can fix it?