| 12345678910111213141516171819 | import { behavior } from './behavior';export function observe(vantOptions, options) {    const { watch } = vantOptions;    options.behaviors.push(behavior);    if (watch) {        const props = options.properties || {};        Object.keys(watch).forEach(key => {            if (key in props) {                let prop = props[key];                if (prop === null || !('type' in prop)) {                    prop = { type: prop };                }                prop.observer = watch[key];                props[key] = prop;            }        });        options.properties = props;    }}
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