From 81ddc5c382c3c9f5c802aecea5ab9ca9cb55b2ec Mon Sep 17 00:00:00 2001
From: Chrystal Maria Griffiths <chrystal.griffiths@overleaf.com>
Date: Fri, 18 Sep 2020 12:04:31 +0200
Subject: [PATCH] Merge pull request #3205 from overleaf/ta-as-local-storage

New Custom LocalStorage Implementation

GitOrigin-RevId: f80fd5f9f24af02690a51cf3c57f61f95b90e98e
---
 .../js/infrastructure/local-storage.js        | 45 ++++++++++++
 .../infrastructure/local-storage.test.js      | 72 +++++++++++++++++++
 2 files changed, 117 insertions(+)
 create mode 100644 services/web/frontend/js/infrastructure/local-storage.js
 create mode 100644 services/web/test/frontend/infrastructure/local-storage.test.js

diff --git a/services/web/frontend/js/infrastructure/local-storage.js b/services/web/frontend/js/infrastructure/local-storage.js
new file mode 100644
index 0000000000..8e4f0fb6ab
--- /dev/null
+++ b/services/web/frontend/js/infrastructure/local-storage.js
@@ -0,0 +1,45 @@
+/**
+ * localStorage can throw browser exceptions, for example if it is full We don't
+ * use localStorage for anything critical, so in that case just fail gracefully.
+ */
+
+/**
+ * Catch, log and otherwise ignore errors.
+ *
+ * @param {function} fn localStorage function to call
+ * @param {string?} key Key passed to the localStorage function (if any)
+ * @param {any?} value Value passed to the localStorage function (if any)
+ */
+const callSafe = function(fn, key, value) {
+  try {
+    return fn(key, value)
+  } catch (e) {
+    console.error('localStorage exception', e)
+    return null
+  }
+}
+
+const getItem = function(key) {
+  return JSON.parse(localStorage.getItem(key))
+}
+
+const setItem = function(key, value) {
+  localStorage.setItem(key, JSON.stringify(value))
+}
+
+const clear = function() {
+  localStorage.clear()
+}
+
+const removeItem = function(key) {
+  return localStorage.removeItem(key)
+}
+
+const customLocalStorage = {
+  getItem: key => callSafe(getItem, key),
+  setItem: (key, value) => callSafe(setItem, key, value),
+  clear: () => callSafe(clear),
+  removeItem: key => callSafe(removeItem, key)
+}
+
+export default customLocalStorage
diff --git a/services/web/test/frontend/infrastructure/local-storage.test.js b/services/web/test/frontend/infrastructure/local-storage.test.js
new file mode 100644
index 0000000000..614f0d29ab
--- /dev/null
+++ b/services/web/test/frontend/infrastructure/local-storage.test.js
@@ -0,0 +1,72 @@
+import { expect } from 'chai'
+import sinon from 'sinon'
+
+import customLocalStorage from '../../../frontend/js/infrastructure/local-storage'
+
+describe('localStorage', function() {
+  beforeEach(function() {
+    global.localStorage = {
+      getItem: sinon.stub().returns(null),
+      setItem: sinon.stub(),
+      clear: sinon.stub(),
+      removeItem: sinon.stub()
+    }
+    global.console.error = sinon.stub()
+  })
+
+  afterEach(function() {
+    global.console.error.reset()
+    delete global.localStorage
+  })
+
+  it('getItem', function() {
+    expect(customLocalStorage.getItem('foo')).to.be.null
+
+    global.localStorage.getItem.returns('false')
+    expect(customLocalStorage.getItem('foo')).to.equal(false)
+
+    global.localStorage.getItem.returns('{"foo":"bar"}')
+    expect(customLocalStorage.getItem('foo')).to.deep.equal({ foo: 'bar' })
+
+    global.localStorage.getItem.throws(new Error('Nope'))
+    expect(customLocalStorage.getItem('foo')).to.be.null
+    expect(global.console.error).to.be.calledOnce
+  })
+
+  it('setItem', function() {
+    customLocalStorage.setItem('foo', 'bar')
+    expect(global.localStorage.setItem).to.be.calledOnceWith('foo', '"bar"')
+    global.localStorage.setItem.reset()
+
+    customLocalStorage.setItem('foo', true)
+    expect(global.localStorage.setItem).to.be.calledOnceWith('foo', 'true')
+    global.localStorage.setItem.reset()
+
+    customLocalStorage.setItem('foo', { bar: 1 })
+    expect(global.localStorage.setItem).to.be.calledOnceWith('foo', '{"bar":1}')
+    global.localStorage.setItem.reset()
+
+    global.localStorage.setItem.throws(new Error('Nope'))
+    expect(customLocalStorage.setItem('foo', 'bar')).to.be.null
+    expect(global.console.error).to.be.calledOnce
+  })
+
+  it('clear', function() {
+    customLocalStorage.clear()
+    expect(global.localStorage.clear).to.be.calledOnce
+
+    global.localStorage.clear.throws(new Error('Nope'))
+    expect(customLocalStorage.clear()).to.be.null
+    expect(global.console.error).to.be.calledOnce
+  })
+
+  it('removeItem', function() {
+    customLocalStorage.removeItem('foo')
+    expect(global.localStorage.removeItem).to.be.calledOnceWith('foo')
+    global.localStorage.removeItem.reset()
+
+    global.localStorage.removeItem.throws(new Error('Nope'))
+    expect(customLocalStorage.removeItem('foo')).to.be.null
+    expect(global.console.error).to.be.calledOnce
+  })
+})