Function traverseNonSpaceNodes

src/buildHTML.ts:141–197

(
    nodes: HtmlDomNode[],
    callback: (arg0: HtmlDomNode, arg1: HtmlDomNode) =>
        HtmlDomNode | null | void,
    prev: {
        node: HtmlDomNode,
        insertAfter?: (arg0: HtmlDomNode) => void,
    },
    next: HtmlDomNode | null | undefined,
    isRoot: boolean,
)

// function to insert after it. `next` is a node that will be added to the right.
// Used for bin cancellation and inserting spacings.
const traverseNonSpaceNodes = function(
    nodes: HtmlDomNode[],
    callback: (arg0: HtmlDomNode, arg1: HtmlDomNode) =>
        HtmlDomNode | null | void,
    prev: {
        node: HtmlDomNode,
        insertAfter?: (arg0: HtmlDomNode) => void,
    },
    next: HtmlDomNode | null | undefined,
    isRoot: boolean,
) {
    if (next) { // temporarily append the right node, if exists
        nodes.push(next);
    }
    let i = 0;
    for (; i < nodes.length; i++) {
        const node = nodes[i];
        const partialGroup = checkPartialGroup(node);

        if (partialGroup) { // Recursive DFS
            // TODO(ts): partialGroup.children is ReadonlyArray but this
            // function mutates the array (insertAfter splices into it).
            traverseNonSpaceNodes(partialGroup.children as HtmlDomNode[],
                callback, prev, null, isRoot);
            continue;
        }

        // Ignore explicit spaces (e.g., \;, \,) when determining what implicit
        // spacing should go between atoms of different classes
        const nonspace = !node.hasClass("mspace");
        if (nonspace) {
            const result = callback(node, prev.node);
            if (result) {
                if (prev.insertAfter) {
                    prev.insertAfter(result);
                } else { // insert at front
                    nodes.unshift(result);
                    i++;
                }
            }
        }

        if (nonspace) {
            prev.node = node;
        } else if (isRoot && node.hasClass("newline")) {
            prev.node = makeSpan(["leftmost"]); // treat like beginning of line
        }
        prev.insertAfter = (index => n => {
            nodes.splice(index + 1, 0, n);
            i++;
        })(i);
    }

    if (next) {
        nodes.pop();
    }
};