lib/rules/prefer-const.js
function findUp(node, type, shouldStop) {
    if (!node || shouldStop(node)) {
        return null;
    }
    if (node.type === type) {
        return node;
    }
    return findUp(node.parent, type, shouldStop);
}
function findUp(node, type, shouldStop) {
    if (!node || shouldStop(node)) {
        return null;
    }
    if (node.type === type) {
        return node;
    }
    return findUp(node.parent, type, shouldStop);
}
function findUp ( node , type , shouldStop ) { if ( ! node || shouldStop ( node ) ) { return null ; } if ( node . type === type ) { return node ; } return findUp ( node . parent , type , shouldStop ) ; }
Finds the nearest parent of node with a given type.

@param {ASTNode} node – The node to search from.
@param {string} type – The type field of the parent node.
@param {Function} shouldStop – a predicate that returns true if the traversal should stop, and false otherwise.
@returns {ASTNode} The closest ancestor with the specified type; null if no such ancestor exists.
Finds the nearest parent of node with a given type .