diff options
Diffstat (limited to 'src/data/composite/data/withPropertyFromList.js')
-rw-r--r-- | src/data/composite/data/withPropertyFromList.js | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/src/data/composite/data/withPropertyFromList.js b/src/data/composite/data/withPropertyFromList.js new file mode 100644 index 0000000..a2c66d7 --- /dev/null +++ b/src/data/composite/data/withPropertyFromList.js @@ -0,0 +1,82 @@ +// Gets a property from each of a list of objects (in a dependency) and +// provides the results. +// +// This doesn't alter any list indices, so positions which were null in the +// original list are kept null here. Objects which don't have the specified +// property are retained in-place as null. +// +// See also: +// - withPropertiesFromList +// - withPropertyFromObject +// +// More list utilities: +// - excludeFromList +// - fillMissingListItems +// - withFilteredList, withMappedList, withSortedList +// - withFlattenedList, withUnflattenedList +// + +import {input, templateCompositeFrom} from '#composite'; + +function getOutputName({list, property, prefix}) { + if (!property) return `#values`; + if (prefix) return `${prefix}.${property}`; + if (list) return `${list}.${property}`; + return `#list.${property}`; +} + +export default templateCompositeFrom({ + annotation: `withPropertyFromList`, + + inputs: { + list: input({type: 'array'}), + property: input({type: 'string'}), + prefix: input.staticValue({type: 'string', defaultValue: null}), + }, + + outputs: ({ + [input.staticDependency('list')]: list, + [input.staticValue('property')]: property, + [input.staticValue('prefix')]: prefix, + }) => + [getOutputName({list, property, prefix})], + + steps: () => [ + { + dependencies: [input('list'), input('property')], + compute: (continuation, { + [input('list')]: list, + [input('property')]: property, + }) => continuation({ + ['#values']: + list.map(item => item[property] ?? null), + }), + }, + + { + dependencies: [ + input.staticDependency('list'), + input.staticValue('property'), + input.staticValue('prefix'), + ], + + compute: (continuation, { + [input.staticDependency('list')]: list, + [input.staticValue('property')]: property, + [input.staticValue('prefix')]: prefix, + }) => continuation({ + ['#outputName']: + getOutputName({list, property, prefix}), + }), + }, + + { + dependencies: ['#values', '#outputName'], + compute: (continuation, { + ['#values']: values, + ['#outputName']: outputName, + }) => + continuation.raiseOutput({[outputName]: values}), + }, + ], +}); |