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拡張機能にプレイリストを表すオブジェクトがあり、それをchrome.storage.syncに保存する必要があります。

私は 4096 QUOTA_BYTES_PER_ITEMについて知っています。つまり、4096key.length + JSON.stringify(val).length未満でなければなりません。しかし、私のオブジェクトは3956 (val stringify の長さ + ket の長さ) で、まだストレージに書き込めません。私は何を間違っていますか?

私のオブジェクトの JSON 文字列化の結果:

{"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}}}

次のコードは、ストレージに格納されるオブジェクト サイズを計算します。

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

そしてそれは戻ってきます

> playlist 3956 

オブジェクトにUTF-8の非ラテン記号が含まれているため、そのような魔法のようなものでしょうか? ネイティブ側の chrome がこの文字のエスケープ (\uXXXX) を実行し、4096 を超える長さになったのではないでしょうか? もしそうなら、どうすればJSON.stringify()そのエスケープを行うことができますか?

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chrome.storage.sync.QUOTA_BYTES_PER_ITEM最大サイズをバイト単位で指定します。Chrome では、JavaScript 文字列は UTF-8 としてエンコードされます。UTF-8 の「文字」のバイト長は可変で、1 または 2 です。

文字列に「Бетономешалка」が含まれています。文字列の長さは 13 ですが、バイト サイズは 26 です。

文字のサイズを検出するにはstring.charCodeAt(index)、指定したインデックスで文字列の文字コードを取得するために使用できます。この数値が 256 より小さい場合 (<= 0xFF)、1 バイトで構成されます。それ以外の場合は、2 バイトになります。
文字列内のバイト数を数えるその他の方法は、JavaScript 文字列内のバイト数は? にリストされています。.

于 2014-07-18T13:16:26.140 に答える