npm install @pallad/builder
Whenever you use a builder pattern, sometimes certain methods needs be called conditionally. For those cases you need to break the chaining.
const queryBuilder = createQueryBuilder();
if (hasFilter) {
queryBuilder.where() // do filters
}
return queryBuilder.where() // work on builder again
That is very annoying and many times unnecessary complicates the code. @pallad/builder
provides Builder
class that
has runIf
and run
helper methods. The most useful is defeinitely runIf
.
return createQueryBuilder()
.runIf(hasFilter, () => {
queryBuilder.where() // do filters
})
.where() // keep working on builder
Much cleaner.
In order to use Builder
in your builder patterns you need to either extend it.
import {Builder} from '@pallad/builder';
class YourCustomBuilder extends Builder {
}
Or apply on existing object
import {Builder} from '@pallad/builder';
const existingBuilder = Builder.extend(someBuilderInstance);
runIf
executes provided function only if condition
is truthy.
If it is not, then returns current instance.
new CustomBuilder()
.runIf(hasEnabledSorting, (builder) => {
builder.setupSorting(); // ran if `hasEnabledSorting` is truthy
})
run
just always executes provided function.
Very handy when you need to setup huge builder but want to split it into several other functions.
new CustomBuilder()
.run(setupFilters)
.run(setupSorting)
.run(setupPagination)
.run(setupTenancy)
Both run
and runIf
might return some result.
If that result is not undefined
or null
then that result is being returned back.
const builder = new CustomBuilder();
const result = builder.runIf(true, () => {
return new CustomBuilder(); // return new instance
});
result === builder // false
Otherwise current instance gets returned
const builder = new CustomBuilder();
const result = builder.runIf(false, () => {
// do nothing
});
result === builder // true