Creating helper methods for the setTimeout uses

Abstracting out some of the setTimeout patterns that have popped up in
the code to make the intention clearer.

src/js/main.js

@@ -33,7 +33,7 @@ window._gaq = (typeof _gaq !== 'undefined') ? _gaq : {
 
     regexper.bindListeners();
 
-    setTimeout(() => {
+    util.tick().then(() => {
       window.dispatchEvent(util.customEvent('hashchange'));
     });
   }
@@ -44,10 +44,6 @@ window._gaq = (typeof _gaq !== 'undefined') ? _gaq : {
       .then(parser => {
         parser.render();
       })
-      .catch(error => {
-        setTimeout(() => {
-          throw error;
-        });
-      });
+      .catch(util.exposeError);
   });
 }());

src/js/parser/javascript.js

@@ -1,6 +1,7 @@
 import Snap from 'snapsvg';
 import _ from 'lodash';
 
+import util from '../util.js';
 import javascript from './javascript/parser.js';
 import ParserState from './javascript/parser_state.js';
 
@@ -46,18 +47,11 @@ export default class Parser {
   parse(expression) {
     this._addClass('loading');
 
-    return new Promise((resolve, reject) => {
-      setTimeout(() => {
-        try {
-          javascript.Parser.SyntaxNode.state = this.state;
+    return util.tick().then(() => {
+      javascript.Parser.SyntaxNode.state = this.state;
 
-          this.parsed = javascript.parse(expression.replace(/\n/g, '\\n'));
-          resolve(this);
-        }
-        catch(e) {
-          reject(e);
-        }
-      });
+      this.parsed = javascript.parse(expression.replace(/\n/g, '\\n'));
+      return this;
     });
   }
 

src/js/parser/javascript/node.js

@@ -57,15 +57,13 @@ export default class Node {
     return this.container.transform(matrix);
   }
 
-  deferredStep() {
-    return new Promise((resolve, reject) => {
-      setTimeout(() => {
-        if (this.state.cancelRender) {
-          reject('Render cancelled');
-        } else {
-          resolve.apply(this, arguments);
-        }
-      }, 1);
+  deferredStep(value) {
+    return util.tick().then(() => {
+      if (this.state.cancelRender) {
+        throw 'Render cancelled';
+      }
+
+      return value;
     });
   }
 

src/js/regexper.js

@@ -97,11 +97,7 @@ export default class Regexper {
     this.state = '';
 
     if (expression !== '') {
-      this.renderRegexp(expression).catch(message => {
-        setTimeout(() => {
-          throw message;
-        });
-      });
+      this.renderRegexp(expression).catch(util.exposeError);
     }
   }
 
@@ -147,10 +143,8 @@ export default class Regexper {
     if (this.running) {
       this.running.cancel();
 
-      return new Promise((resolve, reject) => {
-        setTimeout(() => {
-          resolve(this.renderRegexp(expression));
-        }, 10);
+      util.wait(10).then(() => {
+        return this.renderRegexp(expression);
       });
     }
 

src/js/util.js

@@ -71,9 +71,28 @@ function spaceVertically(items, options) {
   }
 }
 
+function wait(delay) {
+  return new Promise((resolve, reject) => {
+    setTimeout(resolve, delay);
+  });
+}
+
+function tick() {
+  return wait(0);
+}
+
+function exposeError(error) {
+  tick().then(() => {
+    throw error;
+  });
+}
+
 export default {
   customEvent,
   normalizeBBox,
   spaceHorizontally,
-  spaceVertically
+  spaceVertically,
+  wait,
+  tick,
+  exposeError
 };