Function selectChild

tensorboard/plugins/graph/tf_graph_common/common.ts:119–143

(
  container,
  tagName: string,
  className?: string | string[]
)

 * @return selection of the element, or an empty selection
 */
export function selectChild(
  container,
  tagName: string,
  className?: string | string[]
): d3.Selection<any, any, any, any> {
  let children = container.node().childNodes;
  for (let i = 0; i < children.length; i++) {
    let child = children[i];
    if (child.tagName === tagName) {
      if (className instanceof Array) {
        let hasAllClasses = true;
        for (let j = 0; j < className.length; j++) {
          hasAllClasses =
            hasAllClasses && child.classList.contains(className[j]);
        }
        if (hasAllClasses) {
          return d3.select(child);
        }
      } else if (!className || child.classList.contains(className)) {
        return d3.select(child);
      }
    }
  }
  return d3.select(null);
}

/**
 * Given a container d3 selection, select a child svg element of a given tag