UTF-8 テキストファイルを読み込む ref: http://qiita.com/tom-u/items/a076a77b0cc023a29f65

read_utf8_example.js

function app_read(handle, scpt='') {
    let a = Application.currentApplication()
    a.includeStandardAdditions = true
    return a.runScript(`on run argv
        read (item 1 of argv) ${scpt}
    end`, {in:'AppleScript', withParameters:handle})
}

app = Application.currentApplication()
app.includeStandardAdditions = true

p = '/Users/uchcode/Desktop/example.txt'
h = app.openForAccess(p)
r = app_read(h,'as «class utf8»')
app.closeAccess(p)

console.log(r)