{"record":{"id":"c8336d75ad4d6981","repo":"Meituan-Dianping/mpvue","slug":"transition-property-key-is-declared-in-enter","errorCode":null,"errorMessage":"transition property \"${key}\" is declared in enter starting class (.${startClass}), but not declared anywhere in enter ending class (.${endClass}), enter active cass (.${activeClass}) or the element's default styling. Note in Weex, CSS properties need explicit values to be transitionable.","messagePattern":"transition property \"(.+?)\" is declared in enter starting class \\(\\.(.+?)\\), but not declared anywhere in enter ending class \\(\\.(.+?)\\), enter active cass \\(\\.(.+?)\\) or the element's default styling\\. Note in Weex, CSS properties need explicit values to be transitionable\\.","errorType":"console","errorClass":null,"httpStatus":null,"severity":"error","filePath":"src/platforms/weex/runtime/modules/transition.js","lineNumber":243,"sourceCode":"}\n\n// determine the target animation style for an entering transition.\nfunction getEnterTargetState (el, stylesheet, startClass, endClass, activeClass, vm) {\n  const targetState = {}\n  const startState = stylesheet[startClass]\n  const endState = stylesheet[endClass]\n  const activeState = stylesheet[activeClass]\n  // 1. fallback to element's default styling\n  if (startState) {\n    for (const key in startState) {\n      targetState[key] = el.style[key]\n      if (\n        process.env.NODE_ENV !== 'production' &&\n        targetState[key] == null &&\n        (!activeState || activeState[key] == null) &&\n        (!endState || endState[key] == null)\n      ) {\n        warn(\n          `transition property \"${key}\" is declared in enter starting class (.${startClass}), ` +\n          `but not declared anywhere in enter ending class (.${endClass}), ` +\n          `enter active cass (.${activeClass}) or the element's default styling. ` +\n          `Note in Weex, CSS properties need explicit values to be transitionable.`\n        )\n      }\n    }\n  }\n  // 2. if state is mixed in active state, extract them while excluding\n  //    transition properties\n  if (activeState) {\n    for (const key in activeState) {\n      if (key.indexOf('transition') !== 0) {\n        targetState[key] = activeState[key]\n      }\n    }\n  }\n  // 3. explicit endState has highest priority","sourceCodeStart":225,"sourceCodeEnd":261,"githubUrl":"https://github.com/Meituan-Dianping/mpvue/blob/6c5d78ee04f58c6d782c456dfcf0fe63c0b7f89b/src/platforms/weex/runtime/modules/transition.js#L225-L261","documentation":"Error \"transition property \"${key}\" is declared in enter starting class (.${startClass}), but not declared anywhere in enter ending class (.${endClass}), enter active cass (.${activeClass}) or the element's default styling. Note in Weex, CSS properties need explicit values to be transitionable.\" thrown in Meituan-Dianping/mpvue.","triggerScenarios":"Thrown at src/platforms/weex/runtime/modules/transition.js:243 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Declare the transitioning property with an explicit value in the enter ending class (.endClass), the enter active class (.activeClass), or the element's default styling","In Weex CSS every transitionable property needs a concrete start and end value — implicit/undefined values cannot be animated","Double-check the property name spelling in the stylesheet classes so the start class key exists in the target classes too"],"exampleFix":null,"handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"6c5d78ee04f58c6d782c456dfcf0fe63c0b7f89b","analyzedAt":"2026-09-02T05:17:40.946Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-09T11:17:12.671Z"}