‘react-scripts’ is not recognized as an internal or external command

I’ve got a maven project, within which is JavaScript project cloned as a git sub-module. So the directory structure looks like mavenapp/src/main/javascript/[npm project files] Inside my package.json, the test looks like this: but when I try to run npm test, it says ‘react-scripts’ is not recognized as an internal or external command, Interestingly, when I clone the … Read more

Check if a variable is a string in JavaScript

You can use typeof operator: Example from this webpage. (Example was slightly modified though). This won’t work as expected in the case of strings created with new String(), but this is seldom used and recommended against[1][2]. See the other answers for how to handle these, if you so desire. The Google JavaScript Style Guide says to never use primitive object … Read more

What is the “right” JSON date format?

JSON itself does not specify how dates should be represented, but JavaScript does. You should use the format emitted by Date‘s toJSON method: 2012-04-23T18:25:43.511Z Here’s why: It’s human readable but also succinct It sorts correctly It includes fractional seconds, which can help re-establish chronology It conforms to ISO 8601 ISO 8601 has been well-established internationally for more than a decade ISO 8601 is endorsed … Read more

JavaScript null check

An “undefined variable” is different from the value undefined. An undefined variable: A variable with the value undefined: When a function takes an argument, that argument is always declared even if its value is undefined, and so there won’t be any error. You are right about != null followed by !== undefined being useless, though.