As of January 2018 this repo is no longer under active development. It will, however, remain open source.
Perseus is Khan Academy's new exercise question editor and renderer. It allows you to create and display interactive questions.
Our test page isn't much yet, but you can check out a live demo of it here!
To get the dev server running locally, try
make server PORT=9000
which will run the local perseus server on localhost:9000.
Then visit http://localhost:9000/.
To package perseus for distribution, run
make build and to package a debug-friendly build, run
build and the
server make targets will run
npm install but you can also run it yourself to install all node dependencies.
Perseus makes a couple of assumptions about the environment that it's loaded
into. Specifically, it expects the following libraries to be available on the
window object. (If any of them change in a backwards-incompatible way,
you'll likely need to bump the Perseus major version -- see the "Versioning"
externalVals in webpack.config.js)
Also, the following global variables are used, if present:
icu(a subset of the localeplanet api is depended on, as covered by
icu-slim.jsfrom our fork of localeplanet)
For an example of supplying these dependencies, or to get an npm package of perseus with these dependencies built-in, see perseus-configured
Perseus uses two types of version numbers: the version of the itemData/content
that can be sent to
Renderer, and the version of the api
exposed through the
Renderer apiOptions prop. These
are set in
Item data versioning has two subtypes of versions: a global
for the itemData/content format sent to ItemRenderer/Renderer, and per-widget
version numbers for the
options sent to each widget. All of these version
numbers exist both in perseus.js and in the itemData saved to the datastore
by the Perseus editor.
Each of these versions consists of a major and minor version number.
A perseus version can render an itemData version iff its global
itemDataVersion and each of its widget versions are greater than or equal
to those sent to perseus as itemData. A major version increase will happen
when the saving format of this itemData has changed. Perseus clients should
not need to care about this distinction, but it is important to Perseus'
implementation of backwards-compatibility.
The version of the
apiOptions prop sent to
is stored on
Perseus.apiVersion. A minor version increase indicates an
optional additional parameter to this interface. A major version increase
indicates a not-backwards-compatible change to this API. A perseus client
should rely on a specific major version of perseus, and should be able to
use any future minor version increase without changes, but not necessarily
previous minor versions. For example, if a client begins using version 1.2,
Perseus api versions 1.3 or 1.4 will work transparently, but Perseus api
versions 1.0, 1.1, 2.0, or 2.2 will not work.
The KA mobile apps are also clients of Perseus, and the way that Perseus is integrated into the apps requires that we enforce some additional versioning constraints. For specifics, check out the Forge page.
See CONTRIBUTING.md for a walkthrough of how some of the Perseus code works and how to extend it.