fix getValue undefined

[lceric]

<template>
  <div class="btn">这是一个btn</div>
</template>

<script>
export default {
  props: {
    /**
     * 尺寸
     * @optional mini|small|medium|large
     */
    size: {
      type: String,
      default: 'medium',
    },
    /**
     * 禁用状态
     */
    disabled: String,
  },
  created() {
    // if remove the following line code, will be ok
    const { size, disabled } = this.$props
    // if (size) {
    //   console.log(size)
    // }
    // if (disabled) {
    //   console.log(disabled)
    // }
  },
}
</script>

In the process of analysis, disabled props, this.getValue(property.key) will return undefined.

{"type":"ObjectProperty","start":241,"end":245,"loc":{"start":{"line":18,"column":12},"end":{"line":18,"column":16}},"range":[241,245],"extra":{"shorthand":true},"method":false,"key":{"type":"Identifier","start":241,"end":245,"loc":{"start":{"line":18,"column":12},"end":{"line":18,"column":16},"identifierName":"size"},"range":[241,245],"name":"size"},"computed":false,"shorthand":true,"value":{"type":"Identifier","start":241,"end":245,"loc":{"start":{"line":18,"column":12},"end":{"line":18,"column":16},"identifierName":"size"},"range":[241,245],"name":"size"}}
"medium"
{"type":"ObjectProperty","start":247,"end":255,"loc":{"start":{"line":18,"column":18},"end":{"line":18,"column":26}},"range":[247,255],"extra":{"shorthand":true},"method":false,"key":{"type":"Identifier","start":247,"end":255,"loc":{"start":{"line":18,"column":18},"end":{"line":18,"column":26},"identifierName":"disabled"},"range":[247,255],"name":"disabled"},"computed":false,"shorthand":true,"value":{"type":"Identifier","start":247,"end":255,"loc":{"start":{"line":18,"column":18},"end":{"line":18,"column":26},"identifierName":"disabled"},"range":[247,255],"name":"disabled"}}
undefined
Waiting for the debugger to disconnect...
/Users/lichao/Documents/workspace/open-source/vue-sfc-md/node_modules/@vuedoc/parser/lib/parser/AbstractParser.js:172
          name = this.getValue(property.key).value;
                                            ^

TypeError: Cannot read property 'value' of undefined
    at /Users/lichao/Documents/workspace/open-source/vue-sfc-md/node_modules/@vuedoc/parser/lib/parser/AbstractParser.js:172:45