Add support for the property spread

[gajus]

Spec: https://github.com/sebmarkbage/ecmascript-rest-spread

Subject code that triggers error:

style = {
    ...this.props.style
}

Error:

TypeError: Cannot read property 'loc' of undefined
    at EventEmitter.checkObjectExpression (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/eslint-plugin-objects/lib/rules/no-object-property-split.js:15:60)
    at emitOne (events.js:95:20)
    at EventEmitter.emit (events.js:182:7)
    at NodeEventGenerator.enterNode (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/eslint/lib/util/node-event-generator.js:42:22)
    at CodePathAnalyzer.enterNode (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/eslint/lib/code-path-analysis/code-path-analyzer.js:591:23)
    at CommentEventGenerator.enterNode (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/eslint/lib/util/comment-event-generator.js:98:23)
    at Controller.traverser.traverse.enter (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/eslint/lib/eslint.js:843:36)
    at Controller.__execute (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/estraverse/estraverse.js:397:31)
    at Controller.traverse (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/estraverse/estraverse.js:501:28)
    at Controller.Traverser.controller.traverse (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/eslint/lib/util/traverser.js:38:33)
    at EventEmitter.module.exports.api.verify (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/eslint/lib/eslint.js:840:23)
    at processText (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/eslint/lib/cli-engine.js:187:27)
    at CLIEngine.executeOnText (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/node_modules/eslint/lib/cli-engine.js:672:26)
    at exports.default (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/dist/syntaxes/js/lintText.js:23:16)
    at exports.default (/Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/dist/utilities/lintText.js:39:35)
    at /Users/gajus/Documents/dev/applaudience/showtime-ad-app/node_modules/canonical/dist/utilities/lintFiles.js:44:49

[manovotny]

This error bit me last night too.

I tried working on a fix for a while, but wound up stumped. 😞

[manovotny]

Ok, I did a little more fiddling.

I wouldn't say it "adds support" for spread operators, but it stops the bleeding.

You could add the following code in no-object-property-split.js, at the very top of the for loop checking keys and values to essentially skip checking spread operators, which will not have keys / values and cannot be split on multiple lines.

if (props[i].type === 'ExperimentalSpreadProperty') {
    continue;
}

However, ExperimentalSpreadProperty was not added until ESLint 1.0.0-rc-1 (see release notes), which means eslint-plugin-objects would need to up the minimum required version of eslint to use this check.