Why Directly Testing React Component Methods is Considered Harmful
TIL that directly testing React component methods is actually an antipattern.
TIL - Today I Learned
unpkg: the free CDN for your npm packages
unpkg is a free content delivery network (CDN) that automatically distributes public packages published to npm.
What is npx?
You may have heard of npm, but what about npx?
Move jest.conf Out of Root Directory
TIL how to move a jest.conf file out of the root directory for a project, while still allowing it to respect all of the relative pathing defined in the confi...
How to Target Child Components with Scoped CSS in Vue
TIL how to target a child component with a CSS selector from a parent component that is using Scoped CSS.
The Perils of Underestimating Stories
TIL that while the exact number a team uses to estimate a story is meaningless and varies from team to team, the accuracy of the relative estimate matters qu...
How to Directly Test React Component Methods with Enzyme
TIL how to directly test a React component method using enzyme wrapper.instance()
Tradeoffs between Normalization and Denormalization
TIL the difference between normalized and denormalized schemas for modeling data, and some of the tradeoffs with each.
Why Product Roadmaps are Important
TIL why product roadmaps are important: they provide necessary clarity to internal and external stakeholders, for the coordination and prioritization of medi...
When to Use One Hot Encoding
TIL about One Hot Encoding, and when it is necessary to use as a preprocessing step for machine learning models.
What is a Breaking Change Anyways?
TIL what a breaking change was in the context of a public API or Service.
What do API Keys REALLY do?
TIL the true purpose of API keys: a simple yet important revelation!
How to Use Jest to Mock Constructors
TIL how to mock the constructor function of a node_module during unit tests using jest.
How to Reclaim Purgeable Space on Mac
TIL about Purgeable Disk Space in OSX, and after hours of struggling, how to reclaim it.
SOLID: Dependency Inversion Principle
TIL about the dependency inversion principle, and how it (like most of the other SOLID principles) promotes loose coupling between modules.
SOLID: Interface Segregation Principle
TIL about the interface segregation principle, and how it promotes decoupling of classes in your code through the separation of methods in to role interfaces.
SOLID: Open/Closed Principle
TIL about the open/closed principle, and how it can be used to ensure your code is adaptable to new requirements while remaining resilient to changes.
SOLID: Liskov Substitution Principle
TIL about the liskov substitution principle, and how it ensures the “correctness” of a program.
SOLID: Single Responsibility Principle
TIL about the single responsibility principle, and how it can lead to decoupled classes that make changes less risky.
How to Automock node_modules with jest
TIL how to easily node_modules in unit tests using the jest testing framework from Facebook.
RUN vs CMD in Dockerfile
TIL the difference between RUN and CMD when defining an image via a dockerfile.
Setting Up CSS Modules
TIL how to set up CSS modules for a React application that uses webpack.
Temporal Models
TIL how to create a temporal model of a system using some simplifying assumptions for ease of computation.
Gini Impurity (With Examples)
TIL about Gini Impurity: another metric that is used when training decision trees.
Edge Computing
TIL about edge computing, and how it can lead to optimizations over cloud computing in certain scenarios.
Information Entropy and Information Gain
TIL about Information Entropy and Information Gain, which are key pieces towards determining the relevance of a decision when constructing a decision tree.
No Private Class Members in Python
TIL that Python does not have the ability to make class members (methods, data fields) private.
Public Suffix List
TIL about the public suffix list, which is a list of domains in which browsers will not allow secure cookies to be set
Kubernetes 101
TIL about Kubernetes, Google’s open source container orchestration system.
Agile vs Waterfall Leadership Styles
TIL that the leadership style best suited for a team operating in an agile environment is different from that of a waterfall environment.
Unwrapping React Components for Testing Purposes
TIL how to unwrap react components that are decorated by higher order component wrappers like mobx, to get at the underlying component implementation during ...
Using process.nextTick to test asynchronous actions
TIL how to use process.nextTick to ensure asynchronous actions are resolved before running assertions during tests.
Jest Automock Doesn’t Mock Getters
TIL that Jest module automocking does not mock the getter / setter properties of the target module.
AI and Rational Agents
TIL about the 6 different branches of AI, and what a Rational Agent is.
Javascript Class Basics
TIL about the javascript class keyword introduced in ES6, and dug in to some of the nuances behind it.
URLSearchParams Object
TIL about the URLSearchParams Object, which is useful for parsing URL querystrings in to maps of keys and values.
Composing classes using css-modules
TIL how to compose classes together using the composes keyword provided by css-modules. It has changed my world.
Defining Dependency Versions in package.json
TIL how to properly define dependency versions in a pacakge.json file.
How to initiate a requset using XMLHttpRequest objects
TIL how to initiate a request using native browser XMLHttpRequest objects, instead of a request library that wraps these objects.
location.replace() and location.assign()
TIL how to use location.replace() and location.assign() to change URLs programmatically in the browser.
Fetch API: Options
TIL how to pass headers along with requests initiated by the fetch API.
Semantic Versioning
TIL what semantic versioning is, what each number of the version indicates, and why using a versioning scheme like semantic versioning is important.
process vs. thread
TIL the difference between a process and a thread.
Microservices pt. 1: Defining Microservices
TIL what a microservice is, what the purported benefits of microservices are, and some of the drawbacks of creating a system built from microservices.
instanceof vs. typeof
TIL the difference between instanceof and typeof in javascript.
Flyway Migrations
TIL how to configure the database migration framework Flyway, as well as the difference between Versioned and Repeatable migrations.
Linear Algebra Review
TIL how to calculate the magnitude, normalization, dot product, and cross product of vectors. I wrote a small library that performs the calculations - repo w...
Pattern Matching in SQL
TIL how to properly write a SQL statement using the LIKE operator, including how to use wildcards to match various patterns.
Snapshot Testing with Jest
TIL how to perform snapshot testing using Facebook’s React unit testing framework jest. It is somewhat different than traditional visual regression testing… ...
Webpack: Chunking with Plugins
TIL how to use webpack plugins like ExtractTextPlugin and CommonsChunkPlugin to create smaller chunks out of my webpack bundles.
node: require.cache
TIL that node’s require method maintains a cache of the modules that have been imported. I also learned that it is possible to invalidate this cache.
Webpack: Using loaders
TIL how to use webpack loaders to transpile React code to ES5, and compile .less stylesheets to .css.
Webpack: Configuring webpack-dev-server
TIL how to configure webpack-dev-server (WDS) to both serve files from the publicPath and proxy APIs on different domains to avoid cross site request warning...
Webpack: Paths and Naming
TIL the difference between path and publicPath in webpack, and how the output.filename property can be used to assign files to sub-directories in the path.
Arrow Functions and this
TIL how to leverage ES6 arrow functions to avoid losing “this” when writing functions inside of functions.
Prototypal Inheritance
TIL how to implement an inheritance relationship (from scratch) in javascript using prototypal inheritance.
’async’ script attribute
TIL about the behavior of script loading in an HTML page, when the async attribute is added to a script tag.
‘let’ transpilation in Babel
TIL how Babel transpiles variables defined with let to their ES5 var equivalents, while still maintaining the same block scoping rules that apply to let.
Express response.status(204) Won’t Return Content
TIL that the express response object does not forward content bodies to requestors if the status code of the response is 204: No Content.
node globals vs browser globals
TIL that node programs have different globally accessible objects than those found in the browser.
em vs rem
TIL the difference between em and rem in CSS.
min-width vs max-with in Media Queries
TIL a succinct way to remember the difference between using min-width and max-width in a media query.
What is Firebase
TIL what Firebase is. I followed the tutorial and published a quick app to understand its capabilities.
CSS Positioning
TIL (reviewed) the differences between the 4 CSS position property values: static, fixed, relative, absolute.
Javascript Debugger
TIL of two ways to work debug statements into javascript code.
Optimizing Images for the Web
TIL of some simple tricks to optimize images for the web.
Console.log Output is Sometimes Incorrect in Chrome
TIL that the output of console.log in chrome can be misrepresentative of the actual state of an object at the point of logging.
Spread Operator Does Not Deep Copy Properties
TIL that the spread operator does not perform a deep copy of object properties to the target object.
Quickly Resolving Merge Conflicts from the Command Line
TIL of a quick way to quickly resolve merge conflicts from the command line, in a situation where you know you want to fully accept or reject the merging bra...
CSS specificity and the Console Object
TIL (more like relearned) CSS specificity rules, and (unrelated) some additional methods on the console object other than console.log.
CSS Inline Transformations
TIL that inline elements can’t have transformations applied to them in CSS.
Postgres Extension - CITEXT for Case Insensitive Columns
TIL about Postgresql extensions, particularly the CITEXT extension for making a case insensitive column in a table.
The Difference Betwen app.use and app.all in Express
TIL the difference between app.use and app.all in the context of an express application.
The Benefits of View Models
TIL that view models have utility beyond making data easier to digest by consumers.
Native vs 3rd Party Promise Implementations
TIL that the promise implementation shipped with ES6 is not very performant, and that it is still preferable to use a 3rd party promise library for several r...
Put vs Patch, and Other Fun With HTTP Verbs
TIL the difference between PUT and PATCH, and found a nifty table highlighting
Local State is Ok - Lessons from using Redux
TIL that when using Redux, there are examples of state that are best kept local to a component instead of being managed by the Redux store.
Amortized Time Complexity
TIL that the amortized time complexity of adding an item to an ArrayList in Java is O(1), but that the “worst case” for an add operation is O(n). This caused...
LRU cache
TIL how a standard caching strategy, the Least Recently Used (LRU) cache, works.
Call By Value vs Call By Name
TIL the difference between Call By Value and Call by Name expression evaluation strategies implemented by languages such as Scala.
How to use Bind in javaScript
TIL about the bind method in javaScript and how to use it.
HTML5 Email Templates…
TIL how difficult it is to create emails with rich content…inline CSS and email client incompatibilities for days!
Using JS FileReader
TIL how to use the javascript FileReader to read data from a text file.
Converting Binary Strings to Different Bases
TIL how to convert a binary string to a digit of any base, and how to convert a digit of any base to its corresponding binary string.
Mobile Browser Data Limit
TIL that there exists a hard cap on the amount of data a single webpage can ship to a mobile browser, before the browser crashes.
Cohort Analysis
TIL about cohort analysis, and how it can be used as an input to product strategy.
Synchronous Javascript
TIL that javascript is really a synchronous language with callback capabilities that make it feel asynchronous at times.
Sorting Algorithms
TIL (more like re-learned) the differences between a few basic sorting algorithms: selection sort, insertion sort, and merge sort
Sorting Arrays in Javascript
TIL how the Array.prototype.sort() sorts by default, and how to pass a comparator function in to the sort method if a different sort order is desired.
Using Javascript Object Prototypes
TIL how to use javascript object prototypes, to associate common methods and data types with the “superclass” for a javascript object.
Overwriting Mocks in Jasmine
TIL how to overwrite mocks in tests, by saving them to a variable and modifying the function tied to the object.
Interface vs. Abstract Class
TIL the difference between an interface and an abstract class.
Mocking the Clock Using Jasmine
TIL how to mock the internal clock of a test using jasmine. This was useful for testing methods that rely on a timeout or debounce before firing.
Net Promoter Score (NPS)
TIL of a metric that helps measure customer engagement and loyalty: Net Promoter Score
Mocking Angular Dependencies in Unit Tests
TIL how to properly mock angular dependencies in Unit Tests using the Jasmine test framework.
Git Aliases Are Awesome
TIL about git aliases, and how they can speed up your git workflow.
Hunting Down Performance Issues
TIL what the angular-animate library does, after noticing it was contributing to over 60% of the scripting time necessary to scroll through our grid!
One Time Binding
TIL that angular 1.3 and onwards has a one-time-bind option to pass to interpolated expressions, which tells angular that the data is not expected to change.
Chrome Profiler: Self-Time vs. Total-Time
TIL the difference between self-time and total-time in the Chrome profiler.
Using the Chrome Profiler
TIL how to use the Chrome “Timeline” Profiler to help uncover poorly performing front-end code.
Debounce Strikes Back: This Time with Underscore.js
TIL that underscore.js has an awesome debounce wrapper that grants debouncing capabilities to any custom function.
Why $scope.apply() is Necessary in Custom Directives
TIL why you need to call $scope.apply() when you change the value of $scope properties inside of custom angular directives.
Angular Watchers - What’s the Difference?
TIL what the difference between angular’s watcher offerings are: $watch, $watchCollection, $watchGroup and $watch (objectEquality).
Angular Interpolation vs. ng-bind
TIL that instead of interpolating a data binding in a template (via double curly brace syntax), you can accomplish the same thing by adding the ng-bind direc...
Angular ng-model-options - Debounce
TIL about the ng-model-options directive, which augments the behavior of an input element bound to a scope property via ng-model.
Github supports templates for Issues and PRs
TIL that github now supports templates for both Issues and Pull Requests.
Underscore.js
TIL about Underscore.js (an awesome javascript util library) that prevented me from needing to write a custom dictionary-parsing method.
Javascript - Call by Sharing?
TIL that there is a programming language evaluation strategy called “call by sharing,” and that Javascript implements this approach.
Service Design in Angular
TIL how to design a service in Angular that encapsulates the actions necessary to supply data to a controller.
angular.equals for JSON Object Comparison
TIL that angular has an “equals” method that does a deep comparison between objects to determine equality.
Angular Services Maintain State Between Browser Refreshes
TIL that angular services maintain internal state until the page is reloaded.
Global Variables in Javascript
TIL that global variables are automatically (magically?) set on window in javascript.
The “Value Add” of Testing
TIL what the true value add of testing is…there is none!
Command Line Shortcuts for Navigating to Beginning and End of a Command
TIL that you can quickly navigate to the beginning and end of a command in the command line by using the shortcuts ctrl+A and ctrl+E.