feat: split .query into .query and .queryKeys

Applies changes from ipfs/interface-datastore/pull/87

Depends on:

- [ ] ipfs/interface-datastore#87
- [ ] ipfs/js-datastore-core#59

package.json

@@ -42,8 +42,11 @@
   },
   "homepage": "https://github.com/ipfs/js-datastore-level#readme",
   "dependencies": {
-    "datastore-core": "^3.0.0",
-    "interface-datastore": "^3.0.3",
+    "datastore-core": "ipfs/js-datastore-core#feat/split-query-into-query-and-query-keys",
+    "interface-datastore": "ipfs/interface-datastore#feat/split-query-into-query-and-query-keys",
+    "it-filter": "^1.0.2",
+    "it-map": "^1.0.5",
+    "it-take": "^1.0.1",
     "level": "^6.0.1"
   },
   "devDependencies": {

src/index.js

@@ -3,15 +3,19 @@
 const {
   Key, Errors, Adapter,
   utils: {
-    filter, map, take, sortAll
+    sortAll
   }
 } = require('interface-datastore')
+const filter = require('it-filter')
+const map = require('it-map')
+const take = require('it-take')
 
 /**
  * @typedef {import('interface-datastore').Datastore} Datastore
  * @typedef {import('interface-datastore').Pair} Pair
  * @typedef {import('interface-datastore').Batch} Batch
  * @typedef {import('interface-datastore').Query} Query
+ * @typedef {import('interface-datastore').KeyQuery} KeyQuery
  * @typedef {import('interface-datastore').Options} QueryOptions
  */
 
@@ -159,41 +163,42 @@ class LevelDatastore extends Adapter {
 
   /**
    * @param {Query} q
-   * @returns {AsyncIterable<Pair>}
    */
   query (q) {
-    let values = true
-    if (q.keysOnly != null) {
-      values = !q.keysOnly
+    let it = this._query({
+      values: true,
+      prefix: q.prefix
+    })
+
+    if (Array.isArray(q.filters)) {
+      it = q.filters.reduce((it, f) => filter(it, f), it)
     }
 
-    const opts = {
-      keys: true,
-      values: values,
-      keyAsBuffer: true
+    if (Array.isArray(q.orders)) {
+      it = q.orders.reduce((it, f) => sortAll(it, f), it)
     }
 
-    // Let the db do the prefix matching
-    if (q.prefix != null) {
-      const prefix = q.prefix.toString()
-      // Match keys greater than or equal to `prefix` and
-      // @ts-ignore
-      opts.gte = prefix
-      // less than `prefix` + \xFF (hex escape sequence)
-      // @ts-ignore
-      opts.lt = prefix + '\xFF'
+    const { offset, limit } = q
+    if (offset) {
+      let i = 0
+      it = filter(it, () => i++ >= offset)
     }
 
-    let it = levelIteratorToIterator(
-      this.db.iterator(opts)
-    )
+    if (limit) {
+      it = take(it, limit)
+    }
 
-    it = map(it, ({ key, value }) => {
-      if (values) {
-        return { key, value }
-      }
-      return /** @type {Pair} */({ key })
-    })
+    return it
+  }
+
+  /**
+   * @param {KeyQuery} q
+   */
+   queryKeys (q) {
+    let it = map(this._query({
+      values: false,
+      prefix: q.prefix
+    }), ({ key }) => key)
 
     if (Array.isArray(q.filters)) {
       it = q.filters.reduce((it, f) => filter(it, f), it)
@@ -202,6 +207,7 @@ class LevelDatastore extends Adapter {
     if (Array.isArray(q.orders)) {
       it = q.orders.reduce((it, f) => sortAll(it, f), it)
     }
+
     const { offset, limit } = q
     if (offset) {
       let i = 0
@@ -214,6 +220,33 @@ class LevelDatastore extends Adapter {
 
     return it
   }
+
+  /**
+   * @param {object} opts
+   * @param {boolean} opts.values
+   * @param {string} [opts.prefix]
+   * @returns {AsyncIterable<Pair>}
+   */
+  _query (opts) {
+    const iteratorOpts = {
+      keys: true,
+      keyAsBuffer: true,
+      values: opts.values
+    }
+
+    // Let the db do the prefix matching
+    if (opts.prefix != null) {
+      const prefix = opts.prefix.toString()
+      // Match keys greater than or equal to `prefix` and
+      // @ts-ignore
+      iteratorOpts.gte = prefix
+      // less than `prefix` + \xFF (hex escape sequence)
+      // @ts-ignore
+      iteratorOpts.lt = prefix + '\xFF'
+    }
+
+    return levelIteratorToIterator(this.db.iterator(iteratorOpts))
+  }
 }
 
 /**