import { Children } from 'react'; /* * Transforms a React `Children` object into an array. The children of a `Step` are * a render prop and we need to call the function to get the children array. */ const childrenToArray = ( children ) => { if ( typeof children === 'function' ) { children = children( { translate: ( string ) => string } ); } return Children.toArray( children ); }; /* * Transforms a tree of elements (Step or deeper) into a sequence with the * following shape: * * [ [ 'next', 'my-sites' ], [ 'continue', 'some-other-step' ] ] * * It achieves this thanks to two premises: * * - Whatever the result type for any given `element` (may be empty element, * leaf element or element with children), return a list, which may or may * not have values. * * - Using `flatMap` rather than `map` preserves the simple list type of the * branching data even as we go up a level in the element tree. For instance, * if element A has two leaves B and C, with * * branching( B ) = [ 'b1', 'b2' ] * * and * * branching( C ) = [ 'c1', 'c2' ] * * then * * branching( A ) = flatten( branching( B ), branching( C ) ) * = [ 'b1', 'b2', 'c1', 'c2' ] * * Using lists and `flatMap` also works nicely with empty values, because the * empty list is a flattening identity, i.e.: * * flatten( xs, [] ) === flatten( xs ) * * The end result is that `flatMap` acts as an all-in-one map-filter-combine * chain. * */ const branching = ( element ) => { // Skip null elements and text nodes if ( ! element || ! element.props ) { return []; } // If the element has a `step` prop, it's the leaf branching node we're looking for if ( element.props.step ) { const typeName = element.type.displayName || element.type.name || 'unknown'; return [ [ typeName.toLowerCase(), element.props.step ] ]; } return childrenToArray( element.props.children ).flatMap( branching ); }; /* * From a JSX tree of a Tour, find how `Next` and `Continue` components link from one * `Step` to another. For example, for a `` that contains a * `` button, the returned branching object will have a record: * { * 'init': { 'next': 'upload-image' } * } * This data is used to skip steps (`Step.skipToNext`) and to figure out if a step is the * last one in a tour (`isLastStep` in tour context). */ export const tourBranching = ( tourTree ) => { const steps = childrenToArray( tourTree.props.children ); return Object.fromEntries( steps.map( ( step ) => [ step.props.name, Object.fromEntries( branching( step ) ) ] ) ); };