n-express-enhancer
toolsets to create javascript function enhancers (decorators but more powerful and robust)enhance a set of functions chain enhancers together auto next for express auto log for express auto metrics for express auto next/log/metrics for express
Install
npm install @financial-times/n-express-enhancer -D
Create Enhancers
upgrade a decorator to an enhancer withcreateEnhancer
import { createEnhancer } from '@financial-times/n-express-enhancer';
// create a decorator with currying
const decorator = targetFunction => (...args) => {
// ...enhancement
return targetFunction(...args);
}
export default createEnhancer(decorator);
Decorators created by currying with arrow functions in ES6 would return a decorated function with
undefined
name, as arrow functions are anonymous. Enhancers upgraded from decorators by
createEnhancer
would return an enhanced function inheriting the original name of the target function, which is useful if you need to access the function name and make it available in the next chained enhancer. Furthermore, enhancers can also enhance a function bundle (functions wrapped as methods in an object), handy for reducing repeated lines to enhance a set of functions.Use Enhancers
enhance a set of functions
export default enhancer({
someFunctionA: () => {},
someFunctionB: () => {},
});
chain enhancers together
import { errorToHandler, compose } from '@financial-times/n-express-enhancer';
const someMiddleware = (req, res) => {};
export default compose(errorToHandler, enhancerA, enhancerB)(someMiddleware);
order of how enhancers would be executed
Available Enhancers
auto next for express
There's an enhancer included in the package that can be used to enhance middleware/controller function in express to next() any error caught to error handler or calling next() on successful middleware execution.From:
const someMiddleware = (req, res, next) => {
try {
//...throw error if needed
next();
} catch(e) {
next(e);
}
};
export default someMiddleware;
To:
import { errorToHandler } from '@financial-times/n-express-enhancer';
const someMiddleware = (req, res) => {
//...throw error if needed
};
export default errorToHandler(someMiddleware);
If you need to use
res.render
in controller, please use enhancedRender
together. This is due to an restriction in express@4.import { enhancedRender } from '@financial-times/n-express-enhancer';
app.use('/route', enhancedRender, enhancedMiddleware);