diff --git a/README.md b/README.md
index 71064cd..684d9f7 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ npm install git+https://github.com/nextapps-de/flexsearch/tree/v0.8-preview
 - Greatly enhanced performance of the whole text encoding pipeline
 - Improved indexing of numeric content (Triplets)
 - Intermediate result sets and `Resolver`
-- Basic Resolver: `and`, `or`, `xor`, `not`, `limit`, `offset`, `enrich`, `resolve`, Output formatter
+- Basic Resolver: `and`, `or`, `xor`, `not`, `limit`, `offset`, `boost`, `resolve`
 - Improved charset collection
 - New charset preset `soundex` which further reduces memory consumption by also increasing "fuzziness"
 - Performance gain when polling tasks to the index by using "Event-Loop-Caches"
@@ -81,10 +81,12 @@ All persistent variants are optimized for larger sized indexes under heavy workl
   - [basic-resolver](example/nodejs-commonjs/basic-resolver)
   - [basic-worker](example/nodejs-commonjs/basic-worker)
   - [basic-worker-extern-config](example/nodejs-commonjs/basic-worker-extern-config)
+  - [basic-export-import](example/nodejs-commonjs/basic-export-import)
   - [document](example/nodejs-commonjs/document)
   - [document-persistent](example/nodejs-commonjs/document-persistent)
   - [document-worker](example/nodejs-commonjs/document-worker)
   - [document-worker-extern-config](example/nodejs-commonjs/document-worker-extern-config)
+  - [document-export-import](example/nodejs-commonjs/document-export-import)
   - [language-pack](example/nodejs-commonjs/language-pack)
 - [nodejs-esm](example/nodejs-esm):
   - [basic](example/nodejs-esm/basic)
@@ -93,10 +95,12 @@ All persistent variants are optimized for larger sized indexes under heavy workl
   - [basic-resolver](example/nodejs-esm/basic-resolver)
   - [basic-worker](example/nodejs-esm/basic-worker)
   - [basic-worker-extern-config](example/nodejs-esm/basic-worker-extern-config)
+  - [basic-export-import](example/nodejs-esm/basic-export-import)
   - [document](example/nodejs-esm/document)
   - [document-persistent](example/nodejs-esm/document-persistent)
   - [document-worker](example/nodejs-esm/document-worker)
   - [document-worker-extern-config](example/nodejs-esm/document-worker-extern-config)
+  - [document-export-import](example/nodejs-esm/document-export-import)
   - [language-pack](example/nodejs-esm/language-pack)
 
 ### Examples Browser
@@ -2315,6 +2319,7 @@ for(let i = 0; i < files.length; i++){
 - You can import language packs by `dist/module/lang/*` when using ESM and by `const EnglishPreset = require("flexsearch/lang/en");` when using CommonJS (Node.js)
 - The method `index.append()` is now deprecated and will be removed in the near future, because it isn't consistent and leads into unexpected behavior when not used properly. You should only use `index.add()` to push contents to the index.
 - Using the `async` variants like `.searchAsync` is now deprecated (but still works), asynchronous responses will always return from Worker-Index and from Persistent-Index, everything else will return a non-promised result. Having both types of methods looks like the developers can choose between them, but they can't.
+- Any of your exports from versions below v0.8 are not compatible to import into v0.8
 
 ## Not finished yet
 
diff --git a/example/nodejs-commonjs/basic-export-import/README.md b/example/nodejs-commonjs/basic-export-import/README.md
new file mode 100644
index 0000000..24ee65e
--- /dev/null
+++ b/example/nodejs-commonjs/basic-export-import/README.md
@@ -0,0 +1,7 @@
+```bash
+npm install
+```
+
+```bash
+node index.js
+```
\ No newline at end of file
diff --git a/example/nodejs-commonjs/basic-export-import/index.js b/example/nodejs-commonjs/basic-export-import/index.js
new file mode 100644
index 0000000..c0bbc00
--- /dev/null
+++ b/example/nodejs-commonjs/basic-export-import/index.js
@@ -0,0 +1,71 @@
+const { Index } = require("flexsearch");
+
+(async function(){
+
+    // you will need to keep the index configuration
+    // they will not export, also every change to the
+    // configuration requires a full re-index
+    const config = {
+        tokenize: "forward"
+    };
+
+    // create a simple index which can store id-content-pairs
+    let index = new Index(config);
+
+    // some test data
+    const data = [
+        'cats abcd efgh ijkl mnop qrst uvwx cute',
+        'cats abcd efgh ijkl mnop qrst cute',
+        'cats abcd efgh ijkl mnop cute',
+        'cats abcd efgh ijkl cute',
+        'cats abcd efgh cute',
+        'cats abcd cute',
+        'cats cute'
+    ];
+
+    // add data to the index
+    data.forEach((item, id) => {
+        index.add(id, item);
+    });
+
+    // perform query
+    let result = index.search("cute cat");
+
+    // display results
+    result.forEach(i => {
+        console.log(data[i]);
+    });
+
+    // EXPORT
+    // -----------------------
+
+    const fs = require("fs").promises;
+
+    await fs.mkdir("./export/").catch(e => {});
+    await index.export(async function(key, data){
+        await fs.writeFile("./export/" + key, data, "utf8");
+    });
+
+    // IMPORT
+    // -----------------------
+
+    // create the same type of index you have used by .export()
+    // along with the same configuration
+    index = new Index(config);
+
+    // load them in parallel
+    const files = await fs.readdir("./export/");
+    await Promise.all(files.map(async file => {
+        const data = await fs.readFile("./export/" + file, "utf8");
+        await index.import(file, data);
+    }));
+
+    // perform query
+    result = index.search("cute cat");
+
+    // display results
+    console.log("-------------------------------------");
+    result.forEach(i => {
+        console.log(data[i]);
+    });
+}());
\ No newline at end of file
diff --git a/example/nodejs-commonjs/basic-export-import/package.json b/example/nodejs-commonjs/basic-export-import/package.json
new file mode 100644
index 0000000..914e4d5
--- /dev/null
+++ b/example/nodejs-commonjs/basic-export-import/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "nodejs-commonjs-basic-export-import",
+  "dependencies": {
+    "flexsearch": "github:nextapps-de/flexsearch#v0.8-preview"
+  }
+}
diff --git a/example/nodejs-commonjs/document-export-import/README.md b/example/nodejs-commonjs/document-export-import/README.md
new file mode 100644
index 0000000..24ee65e
--- /dev/null
+++ b/example/nodejs-commonjs/document-export-import/README.md
@@ -0,0 +1,7 @@
+```bash
+npm install
+```
+
+```bash
+node index.js
+```
\ No newline at end of file
diff --git a/example/nodejs-commonjs/document-export-import/data.json b/example/nodejs-commonjs/document-export-import/data.json
new file mode 100644
index 0000000..1fd5660
--- /dev/null
+++ b/example/nodejs-commonjs/document-export-import/data.json
@@ -0,0 +1,141 @@
+[
+  {
+    "tconst": "tt0000001",
+    "titleType": "short",
+    "primaryTitle": "Carmencita",
+    "originalTitle": "Carmencita",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Documentary",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000002",
+    "titleType": "short",
+    "primaryTitle": "Le clown et ses chiens",
+    "originalTitle": "Le clown et ses chiens",
+    "isAdult": 0,
+    "startYear": "1892",
+    "endYear": "",
+    "runtimeMinutes": "5",
+    "genres": [
+      "Animation",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000003",
+    "titleType": "short",
+    "primaryTitle": "Pauvre Pierrot",
+    "originalTitle": "Pauvre Pierrot",
+    "isAdult": 0,
+    "startYear": "1892",
+    "endYear": "",
+    "runtimeMinutes": "4",
+    "genres": [
+      "Animation",
+      "Comedy",
+      "Romance"
+    ]
+  },
+  {
+    "tconst": "tt0000004",
+    "titleType": "short",
+    "primaryTitle": "Un bon bock",
+    "originalTitle": "Un bon bock",
+    "isAdult": 0,
+    "startYear": "1892",
+    "endYear": "",
+    "runtimeMinutes": "12",
+    "genres": [
+      "Animation",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000005",
+    "titleType": "short",
+    "primaryTitle": "Blacksmith Scene",
+    "originalTitle": "Blacksmith Scene",
+    "isAdult": 0,
+    "startYear": "1893",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Comedy",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000006",
+    "titleType": "short",
+    "primaryTitle": "Chinese Opium Den",
+    "originalTitle": "Chinese Opium Den",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000007",
+    "titleType": "short",
+    "primaryTitle": "Corbett and Courtney Before the Kinetograph",
+    "originalTitle": "Corbett and Courtney Before the Kinetograph",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Short",
+      "Sport"
+    ]
+  },
+  {
+    "tconst": "tt0000008",
+    "titleType": "short",
+    "primaryTitle": "Edison Kinetoscopic Record of a Sneeze",
+    "originalTitle": "Edison Kinetoscopic Record of a Sneeze",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Documentary",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000009",
+    "titleType": "movie",
+    "primaryTitle": "Miss Jerry",
+    "originalTitle": "Miss Jerry",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "45",
+    "genres": [
+      "Romance"
+    ]
+  },
+  {
+    "tconst": "tt0000010",
+    "titleType": "short",
+    "primaryTitle": "Leaving the Factory",
+    "originalTitle": "La sortie de l'usine Lumière à Lyon",
+    "isAdult": 0,
+    "startYear": "1895",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Documentary",
+      "Short"
+    ]
+  }
+]
\ No newline at end of file
diff --git a/example/nodejs-commonjs/document-export-import/index.js b/example/nodejs-commonjs/document-export-import/index.js
new file mode 100644
index 0000000..1f5dd4c
--- /dev/null
+++ b/example/nodejs-commonjs/document-export-import/index.js
@@ -0,0 +1,99 @@
+const { Document, Charset } = require("flexsearch");
+const fs = require("fs").promises;
+
+(async function(){
+
+    // loading test data
+    const data = JSON.parse(await fs.readFile(__dirname + "/data.json", "utf8"));
+
+    // you will need to keep the index configuration
+    // they will not export, also every change to the
+    // configuration requires a full re-index
+    const config = {
+        document: {
+            id: "tconst",
+            store: true,
+            index: [{
+                field: "primaryTitle",
+                tokenize: "forward",
+                encoder: Charset.LatinBalance
+            },{
+                field: "originalTitle",
+                tokenize: "forward",
+                encoder: Charset.LatinBalance
+            }],
+            tag: [{
+                field: "startYear"
+            },{
+                field: "genres"
+            }]
+        }
+    };
+
+    // create the document index
+    let document = new Document(config);
+
+    // add test data
+    for(let i = 0; i < data.length; i++){
+        document.add(data[i]);
+    }
+
+    // perform a query
+    let result = document.search({
+        query: "karmen",
+        tag: {
+            "startYear": "1894",
+            "genres": [
+                "Documentary",
+                "Short"
+            ]
+        },
+        suggest: true,
+        enrich: true,
+        merge: true
+    });
+
+    // output results
+    console.log(result);
+
+    // EXPORT
+    // -----------------------
+
+    await fs.mkdir("./export/").catch(e => {});
+    await document.export(async function(key, data){
+        await fs.writeFile("./export/" + key, data, "utf8");
+    });
+
+    // IMPORT
+    // -----------------------
+
+    // create the same type of index you have used by .export()
+    // along with the same configuration
+    document = new Document(config);
+
+    // load them in parallel
+    const files = await fs.readdir("./export/");
+    await Promise.all(files.map(async file => {
+        const data = await fs.readFile("./export/" + file, "utf8");
+        await document.import(file, data);
+    }))
+
+    // perform query
+    result = document.search({
+        query: "karmen",
+        tag: {
+            "startYear": "1894",
+            "genres": [
+                "Documentary",
+                "Short"
+            ]
+        },
+        suggest: true,
+        enrich: true,
+        merge: true
+    });
+
+    // output results
+    console.log("-------------------------------------");
+    console.log(result);
+}());
\ No newline at end of file
diff --git a/example/nodejs-commonjs/document-export-import/package.json b/example/nodejs-commonjs/document-export-import/package.json
new file mode 100644
index 0000000..a48b758
--- /dev/null
+++ b/example/nodejs-commonjs/document-export-import/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "nodejs-commonjs-document-export-import",
+  "dependencies": {
+    "flexsearch": "github:nextapps-de/flexsearch#v0.8-preview"
+  }
+}
diff --git a/example/nodejs-esm/basic-export-import/README.md b/example/nodejs-esm/basic-export-import/README.md
new file mode 100644
index 0000000..24ee65e
--- /dev/null
+++ b/example/nodejs-esm/basic-export-import/README.md
@@ -0,0 +1,7 @@
+```bash
+npm install
+```
+
+```bash
+node index.js
+```
\ No newline at end of file
diff --git a/example/nodejs-esm/basic-export-import/index.js b/example/nodejs-esm/basic-export-import/index.js
new file mode 100644
index 0000000..aeed3ca
--- /dev/null
+++ b/example/nodejs-esm/basic-export-import/index.js
@@ -0,0 +1,68 @@
+import { Index } from "flexsearch/esm";
+
+// you will need to keep the index configuration
+// they will not export, also every change to the
+// configuration requires a full re-index
+const config = {
+    tokenize: "forward"
+};
+
+// create a simple index which can store id-content-pairs
+let index = new Index(config);
+
+// some test data
+const data = [
+    'cats abcd efgh ijkl mnop qrst uvwx cute',
+    'cats abcd efgh ijkl mnop qrst cute',
+    'cats abcd efgh ijkl mnop cute',
+    'cats abcd efgh ijkl cute',
+    'cats abcd efgh cute',
+    'cats abcd cute',
+    'cats cute'
+];
+
+// add data to the index
+data.forEach((item, id) => {
+    index.add(id, item);
+});
+
+// perform query
+let result = index.search("cute cat");
+
+// display results
+result.forEach(i => {
+    console.log(data[i]);
+});
+
+// EXPORT
+// -----------------------
+
+import { promises as fs } from "fs";
+
+await fs.mkdir("./export/").catch(e => {});
+await index.export(async function(key, data){
+    await fs.writeFile("./export/" + key, data, "utf8");
+});
+
+// IMPORT
+// -----------------------
+
+// create the same type of index you have used by .export()
+// along with the same configuration
+index = new Index(config);
+
+// load them in parallel
+const files = await fs.readdir("./export/");
+await Promise.all(files.map(async file => {
+    const data = await fs.readFile("./export/" + file, "utf8");
+    await index.import(file, data);
+}))
+
+// perform query
+result = index.search("cute cat");
+
+// display results
+console.log("-------------------------------------");
+result.forEach(i => {
+    console.log(data[i]);
+});
diff --git a/example/nodejs-esm/basic-export-import/package.json b/example/nodejs-esm/basic-export-import/package.json
new file mode 100644
index 0000000..fe3354b
--- /dev/null
+++ b/example/nodejs-esm/basic-export-import/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "nodejs-esm-basic-export-import",
+  "type": "module",
+  "dependencies": {
+    "flexsearch": "github:nextapps-de/flexsearch#v0.8-preview"
+  }
+}
diff --git a/example/nodejs-esm/document-export-import/README.md b/example/nodejs-esm/document-export-import/README.md
new file mode 100644
index 0000000..24ee65e
--- /dev/null
+++ b/example/nodejs-esm/document-export-import/README.md
@@ -0,0 +1,7 @@
+```bash
+npm install
+```
+
+```bash
+node index.js
+```
\ No newline at end of file
diff --git a/example/nodejs-esm/document-export-import/data.json b/example/nodejs-esm/document-export-import/data.json
new file mode 100644
index 0000000..1fd5660
--- /dev/null
+++ b/example/nodejs-esm/document-export-import/data.json
@@ -0,0 +1,141 @@
+[
+  {
+    "tconst": "tt0000001",
+    "titleType": "short",
+    "primaryTitle": "Carmencita",
+    "originalTitle": "Carmencita",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Documentary",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000002",
+    "titleType": "short",
+    "primaryTitle": "Le clown et ses chiens",
+    "originalTitle": "Le clown et ses chiens",
+    "isAdult": 0,
+    "startYear": "1892",
+    "endYear": "",
+    "runtimeMinutes": "5",
+    "genres": [
+      "Animation",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000003",
+    "titleType": "short",
+    "primaryTitle": "Pauvre Pierrot",
+    "originalTitle": "Pauvre Pierrot",
+    "isAdult": 0,
+    "startYear": "1892",
+    "endYear": "",
+    "runtimeMinutes": "4",
+    "genres": [
+      "Animation",
+      "Comedy",
+      "Romance"
+    ]
+  },
+  {
+    "tconst": "tt0000004",
+    "titleType": "short",
+    "primaryTitle": "Un bon bock",
+    "originalTitle": "Un bon bock",
+    "isAdult": 0,
+    "startYear": "1892",
+    "endYear": "",
+    "runtimeMinutes": "12",
+    "genres": [
+      "Animation",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000005",
+    "titleType": "short",
+    "primaryTitle": "Blacksmith Scene",
+    "originalTitle": "Blacksmith Scene",
+    "isAdult": 0,
+    "startYear": "1893",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Comedy",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000006",
+    "titleType": "short",
+    "primaryTitle": "Chinese Opium Den",
+    "originalTitle": "Chinese Opium Den",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000007",
+    "titleType": "short",
+    "primaryTitle": "Corbett and Courtney Before the Kinetograph",
+    "originalTitle": "Corbett and Courtney Before the Kinetograph",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Short",
+      "Sport"
+    ]
+  },
+  {
+    "tconst": "tt0000008",
+    "titleType": "short",
+    "primaryTitle": "Edison Kinetoscopic Record of a Sneeze",
+    "originalTitle": "Edison Kinetoscopic Record of a Sneeze",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Documentary",
+      "Short"
+    ]
+  },
+  {
+    "tconst": "tt0000009",
+    "titleType": "movie",
+    "primaryTitle": "Miss Jerry",
+    "originalTitle": "Miss Jerry",
+    "isAdult": 0,
+    "startYear": "1894",
+    "endYear": "",
+    "runtimeMinutes": "45",
+    "genres": [
+      "Romance"
+    ]
+  },
+  {
+    "tconst": "tt0000010",
+    "titleType": "short",
+    "primaryTitle": "Leaving the Factory",
+    "originalTitle": "La sortie de l'usine Lumière à Lyon",
+    "isAdult": 0,
+    "startYear": "1895",
+    "endYear": "",
+    "runtimeMinutes": "1",
+    "genres": [
+      "Documentary",
+      "Short"
+    ]
+  }
+]
\ No newline at end of file
diff --git a/example/nodejs-esm/document-export-import/index.js b/example/nodejs-esm/document-export-import/index.js
new file mode 100644
index 0000000..8322bf5
--- /dev/null
+++ b/example/nodejs-esm/document-export-import/index.js
@@ -0,0 +1,97 @@
+import { Document, Charset } from "flexsearch/esm";
+import { promises as fs } from "fs";
+
+const dirname = import.meta.dirname;
+// loading test data
+const data = JSON.parse(await fs.readFile(dirname + "/data.json", "utf8"));
+
+// you will need to keep the index configuration
+// they will not export, also every change to the
+// configuration requires a full re-index
+const config = {
+    document: {
+        id: "tconst",
+        store: true,
+        index: [{
+            field: "primaryTitle",
+            tokenize: "forward",
+            encoder: Charset.LatinBalance
+        },{
+            field: "originalTitle",
+            tokenize: "forward",
+            encoder: Charset.LatinBalance
+        }],
+        tag: [{
+            field: "startYear"
+        },{
+            field: "genres"
+        }]
+    }
+};
+
+// create the document index
+let document = new Document(config);
+
+// add test data
+for(let i = 0; i < data.length; i++){
+    document.add(data[i]);
+}
+
+// perform a query
+let result = document.search({
+    query: "karmen",
+    tag: {
+        "startYear": "1894",
+        "genres": [
+            "Documentary",
+            "Short"
+        ]
+    },
+    suggest: true,
+    enrich: true,
+    merge: true
+});
+
+// output results
+console.log(result);
+
+// EXPORT
+// -----------------------
+
+await fs.mkdir("./export/").catch(e => {});
+await document.export(async function(key, data){
+    await fs.writeFile("./export/" + key, data, "utf8");
+});
+
+// IMPORT
+// -----------------------
+
+// create the same type of index you have used by .export()
+// along with the same configuration
+document = new Document(config);
+
+// load them in parallel
+const files = await fs.readdir("./export/");
+await Promise.all(files.map(async file => {
+    const data = await fs.readFile("./export/" + file, "utf8");
+    await document.import(file, data);
+}))
+
+// perform query
+result = document.search({
+    query: "karmen",
+    tag: {
+        "startYear": "1894",
+        "genres": [
+            "Documentary",
+            "Short"
+        ]
+    },
+    suggest: true,
+    enrich: true,
+    merge: true
+});
+
+// output results
+console.log("-------------------------------------");
+console.log(result);
diff --git a/example/nodejs-esm/document-export-import/package.json b/example/nodejs-esm/document-export-import/package.json
new file mode 100644
index 0000000..62db8c9
--- /dev/null
+++ b/example/nodejs-esm/document-export-import/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "nodejs-esm-document-export-import",
+  "type": "module",
+  "dependencies": {
+    "flexsearch": "github:nextapps-de/flexsearch#v0.8-preview"
+  }
+}
diff --git a/src/serialize.js b/src/serialize.js
index 0c655e9..2f58312 100644
--- a/src/serialize.js
+++ b/src/serialize.js
@@ -132,10 +132,10 @@ function save(callback, field, key, chunk, index_doc, index_obj, index_prt = 0){
 }
 
 /**
- * @param callback
- * @param field
- * @param index_doc
- * @param index_obj
+ * @param {function(string,string):Promise|void} callback
+ * @param {string|null=} field
+ * @param {number=} index_doc
+ * @param {number=} index_obj
  * @this {Index}
  */
 
@@ -186,6 +186,8 @@ export function exportIndex(callback, field, index_doc, index_obj = 0){
 }
 
 /**
+ * @param {string} key
+ * @param {string|*} data
  * @this {Index}
  */
 
@@ -195,14 +197,14 @@ export function importIndex(key, data){
         return;
     }
     if(is_string(data)){
-        data = JSON.parse(data);
+        data = JSON.parse(/** @type {string} */(data));
     }
 
-    key = key.split(".");
-    if(key[key.length - 1] === "json"){
-        key.pop();
+    const split = key.split(".");
+    if(split[split.length - 1] === "json"){
+        split.pop();
     }
-    key = key.length > 1 ? key[1] : key[0];
+    key = split.length > 1 ? split[1] : split[0];
 
     switch(key){
 
@@ -230,6 +232,10 @@ export function importIndex(key, data){
 }
 
 /**
+ * @param {function(string,string):Promise|void} callback
+ * @param {string|null=} field
+ * @param {number=} index_doc
+ * @param {number=} index_obj
  * @this {Document}
  */
 
@@ -302,6 +308,8 @@ export function exportDocument(callback, field, index_doc = 0, index_obj = 0){
 }
 
 /**
+ * @param key
+ * @param {string|*} data
  * @this {Document}
  */
 
@@ -311,15 +319,15 @@ export function importDocument(key, data){
         return;
     }
     if(is_string(data)){
-        data = JSON.parse(data);
+        data = JSON.parse(/** @type {string} */(data));
     }
 
-    key = key.split(".");
-    if(key[key.length - 1] === "json"){
-        key.pop();
+    const split = key.split(".");
+    if(split[split.length - 1] === "json"){
+        split.pop();
     }
-    const field = key.length > 2 ? key[0] : "";
-    key = key.length > 2 ? key[2] : key[1];
+    const field = split.length > 2 ? split[0] : "";
+    key = split.length > 2 ? split[2] : split[1];
 
     if(!field){