Question

我的扩展程序中有一个代表播放列表的对象，我需要将其保存到 chrome.storage.sync 。

我知道4096 QUOTA_BYTES_PER_ITEM ，这意味着key.length + JSON.stringify(val).length必须小于 4096 。但我的对象是 3956 （val stringify length + ket length），我仍然无法将其写入存储。我做错了什么？

我的对象JSON字符串化结果：

{"playlist":{"state":{"tracks":[{"artist":"In Flames","title":"Delight And Angers (Instrumental)"},{"artist":"Marilyn Manson","title":"Coma Black"},{"artist":"Red Hot Chili Peppers","title":"Can't Stop"},{"artist":"Jack Johnson","title":"Better Together (Hawaiian Version)"},{"artist":"Joel Nielsen","title":"Surface Tension 2"},{"artist":"Katatonia","title":"Deliberation"},{"artist":"Rev Theory","title":"Hell Yeah"},{"artist":"Die drei Friseure ","title":"Parikmaher"},{"artist":"In Flames","title":"Drenched in Fear"},{"artist":"In Flames","title":"A New Dawn"},{"artist":"Before The Dawn","title":"The First Snow/Winter Within"},{"artist":"Corey Taylor & James Root","title":"Zzyzx Road"},{"artist":"In Flames","title":"Ropes"},{"artist":"In Flames","title":"Come Clarity"},{"artist":"Jack Johnson","title":"Better Together"},{"artist":"In Flames","title":"Crawl Through Knives"},{"artist":"Ленинград","title":"День Рождения.а я вот день рожденье не буду справлять!"},{"artist":"Ellen McLain","title":"Still Alive"},{"artist":"Richard Cheese","title":"People Equals Shit "},{"artist":"Papa Roach","title":"Last Resort"},{"artist":"Killswitch Engage","title":"The End of Heartache"},{"artist":"Sonic Syndicate","title":"Denied"},{"artist":"Trivium","title":"Pull Harder On The Strings Of Your Martyr"},{"artist":"Bon Jovi","title":"Last Man Standing"},{"artist":"Jelonek","title":"Beast"},{"artist":"Gorillaz","title":"Feel Good Inc"},{"artist":"Five Finger Death Punch","title":"Falling In Hate"},{"artist":"Metallica","title":"The Memory Remains (Live)"},{"artist":"Richard Z. Kruspe","title":"Wake up"},{"artist":"Nylithia","title":"Infector (Intro)"},{"artist":"Nylithia","title":"Super Mario B Castle Theme"},{"artist":"Scorpions/Скорпионс","title":"Wind Of Change/Ветер Перемен  (Версия на русском языке)"},{"artist":"Michael Andrews","title":"Mad World"},{"artist":"John 5","title":"2 Die 4"},{"artist":"Escape the Fate","title":"This War Is Ours (The Guillotine Part II)"},{"artist":"John 5","title":"Damaged"},{"artist":"Marty Friedman","title":"Dragon Mistress"},{"artist":"Pelican","title":"The Creeper"},{"artist":"JELONEK","title":"BaRock"},{"artist":"Blotted Science","title":"Laser Lobotomy"},{"artist":"The String Quartet Tribute  to NIRVANA","title":"Come As You Are "},{"artist":"String Tribute","title":"Tears Don't Fall (BFMV)"},{"artist":"Papa Roach","title":"Change or Die"},{"artist":"Trivium","title":"Dying in your arms"},{"artist":"Disturbed","title":"Decadance"},{"artist":"Bullet For My Valentine","title":"Turn To Despair"},{"artist":"Metallica","title":"Orion [Instrumental]"},{"artist":"Divination","title":"The Heretic Anthem"},{"artist":"Bullet for my Valentine","title":"Say Goodnight (Acoustic Version)"},{"artist":"Кувалда","title":"Бетономешалка"},{"artist":"Slipknot","title":"Confessions"},{"artist":"Bullet For My Valentine","title":"7 Days (Bonus Track)"},{"artist":"Bullet for My Valentine","title":"Forewer and Always (Acoustic Version)"},{"artist":"Bullet For My Valentine","title":"Hearts Burst Into Fire (Acoustic Version)"},{"artist":"In Flames","title":"Everlost (Part II)"},{"artist":"In Flames","title":"Acoustic Medley"},{"artist":"In Flames","title":"Cloud Connected"},{"artist":"In Flames","title":"Crawl Through Knives"},{"artist":"In Flames","title":"Free Fall"},{"artist":"Metallica","title":"Die, Die My Darling"},{"artist":"Slipknot","title":"Psychosocial (Album Version)"},{"artist":"Korn","title":"Jingle Bells"},{"artist":"Stone Sour","title":"Through Glass"},{"artist":"Slipknot","title":"Snuff"},{"artist":"Звонок в компанию Microsoft","title":"Как крякнуть Висту?"},{"artist":"Furious Ball","title":"Fog"},{"artist":"The Beatles","title":"Yellow Submarine"},{"artist":"Lumen","title":"Космонавт"},{"artist":"Lumen","title":"Государство"},{"artist":"Bullet For My Valentine","title":"Tears Don't Fall (Acoustic) (Bonus Track)"},{"artist":"Karunesh","title":"The Wanderer "}],"currentTrack":0}}}

以下代码计算要存储在存储中的对象大小：

for(var i in obj) {
    console.log(i, JSON.stringify(obj[i]).length + i.length)
}

然后返回

> playlist 3956

我无法理解，因为我的对象中有UTF-8非拉丁符号，可能是这样的魔法？也许原生方面的chrome执行转义（\ uXXXX）这个字符并且长度超过4096？如果是这样，我如何让JSON.stringify()也进行逃避？

Answer 1

chrome.storage.sync.QUOTA_BYTES_PER_ITEM指定字节中的最大大小。在Chrome中，JavaScript字符串编码为UTF-8。 UTF-8“字符”具有可变字节长度，它是1或2。

您的字符串包含“Бетономешалка”。字符串长度为13，但字节大小为26。

要检测字符的大小，可以使用string.charCodeAt(index)在指定的索引处获取字符串的字符代码。如果该数字小于256（＆lt; = 0xFF），则它由一个字节组成。否则它将有两个字节在How many bytes in a JavaScript string?列出了计算字符串中字节数的其他一些方法。

为什么我不会为不太长的字符串收到QUOTA_BYTES_PER_ITEM错误？

2 个答案: