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unist utility to recursively reduce a tree

npm:

npm install unist-util-reduce

constu=require("unist-builder");constreduce=require("unist-util-reduce");constassert=require("assert");consttree=u("tree",[u("leaf","1"),u("node",[u("leaf","2")]),u("void"),u("leaf","3")]);constnewTree=reduce(tree,function(node){if(node.value==="2"){constduplicateNode={ ...node,value:"two"};return[duplicateNode,node];}returnnode;});constexpected=u("tree",[u("leaf","1"),u("node",[u("leaf","two"),u("leaf","2")]),u("void"),u("leaf","3")]);assert.deepEqual(newTree,expected);

NOTE:leaf withvalue2 is visited before it's parentnode. By thetime yourtransform function is invoked, it'schildren will already havebeen passed throughtransform.

• tree - A node of typeParent
• transform - A function with the signature:
  • (node: Node, path: number[], root: Paretn) => Node | Node[]
    • node - TheNode in the tree to be transformed
    • path - The path to reach this node in each level of the tree
    • root - TheParent root node
    • Returns - What you return is passed to.concat() on thechildrenarray of the node's parent.

• unist-util-filter— Create a new tree with all nodes that pass a test
• unist-util-map— Create a new tree with all nodes mapped by a given function
• unist-util-remove— Remove nodes from a tree that pass a test
• unist-util-select— Select nodes with CSS-like selectors

MIT ©Callum Macdonald / GeneroUS Labs