Got rid of metrohash

clientIO · Nov 1, 2019 · 4ce22c8 · 4ce22c8
1 parent 63bfe72
commit 4ce22c8
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Showing 3 changed files with 37 additions and 22 deletions.
diff --git a/package.json b/package.json
@@ -12,8 +12,8 @@
         "check-types": "^7.1.5",
         "content-type": "^1.0.4",
         "handlebars": "^4.0.5",
-        "metrohash": "^2.3.0",
         "moment": "^2.22.2",
+        "hasha": "^5.1.0",
         "mongodb": "^3.1.1",
         "redis": "^2.8.0",
         "request": "^2.88.0"

diff --git a/test/component.js b/test/component.js
@@ -13,7 +13,7 @@ function generateLoremIpsumList(offset, length) {
     const loremArr = lorem.split(' ');
 
     const list = [];
-    for (var i = 0; i < length; i++) {
+    for (let i = 0; i < length; i++) {
         list.push({
             _id: i,
             tag: loremArr[i + offset],
@@ -25,7 +25,9 @@ function generateLoremIpsumList(offset, length) {
     return list;
 }
 
-function clone(list) { return JSON.parse(JSON.stringify(list)); }
+function clone(list) {
+    return JSON.parse(JSON.stringify(list));
+}
 
 describe('component utils', () => {
 
@@ -44,11 +46,11 @@ describe('component utils', () => {
     listPhase2.shift();
     // add new one
     listPhase2.push({
-            _id: 666,
-            tag: 'noTag',
-            flag: 'x',
-            tstamp: new Date()
-        });
+        _id: 666,
+        tag: 'noTag',
+        flag: 'x',
+        tstamp: new Date()
+    });
 
     let state = [];
 
@@ -106,12 +108,13 @@ describe('component utils', () => {
             } = componentUtils.checkListForChanges(listPhase1, state, '_id',
                 {
                     // omit timestamp
-                    mappingFunction: ({ _id, tag, flag }) => ({ _id, tag, flag })
+                    mappingFunction: ({ _id, tag, flag }) => ({ _id, tag, flag }),
+                    includeOldData: true
                 });
 
             // new state should contain all items
             expect(newState.length).to.equal(LIST_SIZE);
-            // expect 8 changes, ale to be of state 'new'
+            // expect 8 changes, all to be of state 'new'
             expect(changes.filter(ch => ch.state === 'new').length).to.equal(LIST_SIZE);
 
             state = newState;
@@ -125,13 +128,23 @@ describe('component utils', () => {
             } = componentUtils.checkListForChanges(listPhase2, state, '_id',
                 {
                     // omit timestamp
-                    mappingFunction: ({ _id, tag, flag }) => ({ _id, tag, flag })
+                    mappingFunction: ({ _id, tag, flag }) => ({ _id, tag, flag }),
+                    includeOldData: true
                 });
 
             // test changes
-            const expected = [ [1, 'changed'], [3, 'changed'], [666, 'new'], [0, 'removed'], [7, 'removed']];
+            const expected = [[1, 'changed'], [3, 'changed'], [666, 'new'], [0, 'removed'], [7, 'removed']];
             // compare to expectation
-            const result = changes.filter((ch, i) => ch.id === expected[i][0] && ch.state === expected[i][1]);
+            const result = changes.filter((ch, i) => {
+                if (ch.state !== expected[i][1]) {
+                    // if state does not match = error, filter out
+                    return false;
+                }
+                if (ch.state === 'removed') {
+                    return ch.oldItem._id === expected[i][0];
+                }
+                return ch.item['_id'] === expected[i][0];
+            });
             expect(result.length).to.equal(expected.length);
 
             // test state

diff --git a/util/component.js b/util/component.js
@@ -1,6 +1,5 @@
 'use strict';
-
-const metrohash128 = require('metrohash').metrohash128;
+const hasha = require('hasha');
 const objectUtil = require('./object');
 
 // some helper functions
@@ -49,10 +48,10 @@ function createMappingFunctionFromCSV(csv) {
  * Using previous state compares items of iterable and returns new state and changes
  * @param {Iterable} iterable
  * @param {Map|Array<Array>} previousState
- * @param {string|function(object)s} idMapping
+ * @param {string|function(object)} idMapping
  *         if string, then idMapping value is used as path to id in item
- *         if function, idMapping is called on item to retreive id of that item
- *         !!WARNING!! for components where big load of items is expected, I recomend pass
+ *         if function, idMapping is called on item to retrieve id of that item
+ *         !!WARNING!! for components where big load of items is expected, I recommend pass
  *         own mapping function, because the generated one adds bit more of load.
  * @param {?Object=} options
  * @param {boolean} options.includeOldData when true, function includes difference in changed item
@@ -82,7 +81,7 @@ function checkListForChanges(iterable, previousState, idMapping, options = {}) {
         includeOldData = false,
         mappingFunction = identity,
         stringifyFunction = JSON.stringify.bind(JSON),
-        hashFn = metrohash128
+        hashFn = hasha
     } = options;
 
     let changes = [];
@@ -105,7 +104,8 @@ function checkListForChanges(iterable, previousState, idMapping, options = {}) {
             // new item
             changes.push({
                 item: origItem,
-                oldItem: null
+                oldItem: null,
+                state: 'new'
             });
         } else if (previousItem.hash === hash) {
             // done with this item, get rid of it
@@ -114,7 +114,8 @@ function checkListForChanges(iterable, previousState, idMapping, options = {}) {
             // changed item
             changes.push({
                 item: origItem,
-                oldItem: previousItem.data
+                oldItem: previousItem.data,
+                state: 'changed'
             });
             // done with this item, get rid of it
             previousState.delete(id);
@@ -123,7 +124,8 @@ function checkListForChanges(iterable, previousState, idMapping, options = {}) {
 
     // at this point, previous state contains only items which were removed
     // so add those
-    changes = changes.concat([...previousState.values()].map(state => ({ item: null, oldItem: state.data })));
+    changes = changes.concat([...previousState.values()]
+        .map(state => ({ item: null, oldItem: state.data, state: 'removed' })));
 
     return {
         changes,