Meituan-Dianping/mpvue · error

<${el.tag} v-for="${alias} in ${exp}">: component lists rend

Error message

<${el.tag} v-for="${alias} in ${exp}">: component lists rendered with v-for should have explicit keys. See https://vuejs.org/guide/list.html#key for more info.

What it means

Error "<${el.tag} v-for="${alias} in ${exp}">: component lists rendered with v-for should have explicit keys. See https://vuejs.org/guide/list.html#key for more info." thrown in Meituan-Dianping/mpvue.

Source

Thrown at packages/weex-template-compiler/build.js:2881

function genFor (
  el,
  state,
  altGen,
  altHelper
) {
  var exp = el.for;
  var alias = el.alias;
  var iterator1 = el.iterator1 ? ("," + (el.iterator1)) : '';
  var iterator2 = el.iterator2 ? ("," + (el.iterator2)) : '';

  if (process.env.NODE_ENV !== 'production' &&
    state.maybeComponent(el) &&
    el.tag !== 'slot' &&
    el.tag !== 'template' &&
    !el.key
  ) {
    state.warn(
      "<" + (el.tag) + " v-for=\"" + alias + " in " + exp + "\">: component lists rendered with " +
      "v-for should have explicit keys. " +
      "See https://vuejs.org/guide/list.html#key for more info.",
      true /* tip */
    );
  }

  el.forProcessed = true; // avoid recursion
  return (altHelper || '_l') + "((" + exp + ")," +
    "function(" + alias + iterator1 + iterator2 + "){" +
      "return " + ((altGen || genElement)(el, state)) +
    '})'
}

function genData (el, state) {
  var data = '{';

  // directives first.

View on GitHub (pinned to 6c5d78ee04)

Solutions

1. Add an explicit :key to the component inside v-for, e.g. <my-item v-for="item in list" :key="item.id">
2. Use stable unique ids, not array index, for lists that reorder
3. This is only required for component elements; plain elements do not need keys

When it happens

Trigger: Thrown at packages/weex-template-compiler/build.js:2881 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Meituan-Dianping/mpvue@6c5d78ee04 (2026-09-02). Data as JSON: /api/errors/48fe61b727a8da7f. Report an issue: GitHub.