Update for new xo linting.

lib/index.js

@@ -1,7 +1,7 @@
 const EventEmitter = require('events');
 const icepick = require('icepick');
 
-const INVALID_ROOT_KEYS = ['layers', 'sources'];
+const INVALID_ROOT_KEYS = new Set(['layers', 'sources']);
 
 const VALID_HOOKS = ['validate'];
 
@@ -12,20 +12,20 @@ const DEFAULT_STYLE = {
 };
 
 class IcepickStyle extends EventEmitter {
-	constructor(inputStyle, opts = {}) {
+	constructor(inputStyle, options = {}) {
 		super();
-		opts = {
+		options = {
 			maxHistoryLength: 100,
 			hooks: {},
-			...opts
+			...options
 		};
 
 		this._hooks = {};
-		this._maxHistoryLength = opts.maxHistoryLength;
+		this._maxHistoryLength = options.maxHistoryLength;
 
 		VALID_HOOKS.forEach(key => {
-			if (opts.hooks[key] && Array.isArray(opts.hooks[key])) {
-				this._hooks[key] = [].concat(opts.hooks[key]);
+			if (options.hooks[key] && Array.isArray(options.hooks[key])) {
+				this._hooks[key] = [].concat(options.hooks[key]);
 			} else {
 				this._hooks[key] = [];
 			}
@@ -84,7 +84,7 @@ class IcepickStyle extends EventEmitter {
 	}
 
 	_assertValidHook(key) {
-		if (VALID_HOOKS.indexOf(key) < 0) {
+		if (!VALID_HOOKS.includes(key)) {
 			throw new Error('Invalid hook type: ' + key);
 		}
 	}
@@ -104,15 +104,15 @@ class IcepickStyle extends EventEmitter {
 		});
 	}
 
-	merge(obj) {
-		const newDoc = icepick.merge(this.current, obj);
+	merge(object) {
+		const newDoc = icepick.merge(this.current, object);
 		this._pushHistory(newDoc);
 	}
 
-	replace(obj) {
+	replace(object) {
 		const newDoc = icepick.replace(this.current, {
 			...DEFAULT_STYLE,
-			...obj
+			...object
 		});
 		this._pushHistory(newDoc);
 	}
@@ -148,20 +148,20 @@ class IcepickStyle extends EventEmitter {
 	/*
 	 * Style functions
 	 */
-	addRoot(key, obj) {
-		if (INVALID_ROOT_KEYS.indexOf(key) > -1) {
+	addRoot(key, object) {
+		if (INVALID_ROOT_KEYS.has(key)) {
 			throw new Error(`Can't add ${key} use add* methods instead`);
 		}
 
 		if (Object.prototype.hasOwnProperty.call(this.current, key)) {
 			throw new Error('Already has root element');
 		}
 
-		return this.modifyRoot(key, obj);
+		return this.modifyRoot(key, object);
 	}
 
-	modifyRoot(key, obj) {
-		if (INVALID_ROOT_KEYS.indexOf(key) > -1) {
+	modifyRoot(key, object) {
+		if (INVALID_ROOT_KEYS.has(key)) {
 			throw new Error(`Can't modify ${key} use modify* methods instead`);
 		}
 
@@ -172,18 +172,18 @@ class IcepickStyle extends EventEmitter {
 			newDoc = icepick.setIn(
 				this.current,
 				[key],
-				icepick.replace(this.current[key], obj)
+				icepick.replace(this.current[key], object)
 			);
 		} else {
-			newDoc = icepick.setIn(this.current, [key], obj);
+			newDoc = icepick.setIn(this.current, [key], object);
 		}
 
 		this._pushHistory(newDoc);
 		return this;
 	}
 
 	removeRoot(key) {
-		if (INVALID_ROOT_KEYS.indexOf(key) > -1) {
+		if (INVALID_ROOT_KEYS.has(key)) {
 			throw new Error(`Can't remove ${key} use remove* methods instead`);
 		}
 
@@ -264,8 +264,8 @@ class IcepickStyle extends EventEmitter {
 		const doc = this.current;
 		const {layers} = doc;
 		const layer = layers[idx];
-		const tmpLayers = icepick.splice(layers, idx, 1);
-		const newLayers = icepick.splice(tmpLayers, newIdx, 0, layer);
+		const temporaryLayers = icepick.splice(layers, idx, 1);
+		const newLayers = icepick.splice(temporaryLayers, newIdx, 0, layer);
 
 		const newDoc = icepick.setIn(
 			doc,