just modify answer of @apsilliers
function syncStore(key, objectToStore) {
var jsonstr = JSON.stringify(objectToStore);
var i = 0;
var storageObj = {};
// split jsonstr into chunks and store them in an object indexed by `key_i`
while(jsonstr.length > 0) {
var index = key + "_" + i++;
// since the key uses up some per-item quota, see how much is left for the value
// also trim off 2 for quotes added by storage-time `stringify`
const maxLength = chrome.storage.sync.QUOTA_BYTES_PER_ITEM - index.length - 2;
var valueLength = jsonstr.length;
if(valueLength > maxLength){
valueLength = maxLength;
}
// trim down segment so it will be small enough even when run through `JSON.stringify` again at storage time
//max try is QUOTA_BYTES_PER_ITEM to avoid infinite loop
var segment = jsonstr.substr(0, valueLength);
for(let i = 0; i < chrome.storage.sync.QUOTA_BYTES_PER_ITEM; i++){
const jsonLength = JSON.stringify(segment).length;
if(jsonLength > maxLength){
segment = jsonstr.substr(0, --valueLength);
}else {
break;
}
}
storageObj[index] = segment;
jsonstr = jsonstr.substr(valueLength);
}
also function to read each partition and merge again
function syncGet(key, callback) {
chrome.storage.sync.get(key, (data) => {
console.log(data[key]);
console.log(typeof data[key]);
if(data != undefined && data != "undefined" && data != {} && data[key] != undefined && data[key] != "undefined"){
const keyArr = new Array();
for(let i = 0; i <= data[key].count; i++) {
keyArr.push(`${data[key].prefix}${i}`)
}
chrome.storage.sync.get(keyArr, (items) => {
console.log(data)
const keys = Object.keys( items );
const length = keys.length;
let results = "";
if(length > 0){
const sepPos = keys[0].lastIndexOf("_");
const prefix = keys[0].substring(0, sepPos);
for(let x = 0; x < length; x ++){
results += items[`${prefix }_${x}`];
}
callback(JSON.parse(results));
return;
}
callback(undefined);
});
} else {
callback(undefined);
}
});
}
it tested and it works for my case