Adding documentation to util.js

This commit is contained in:
Jeff Avallone 2015-04-12 16:03:17 -04:00
parent d4b4b2111e
commit 7de958dc25

View File

@ -1,5 +1,13 @@
// Utility functions used elsewhere in the codebase. Most JavaScript files on
// the site use some functions defined in this file.
import _ from 'lodash';
// Generate an `Event` object for triggering a custom event.
//
// - __name__ - Name of the custom event. This should be a String.
// - __detail__ - Event details. The event details are provided to the event
// handler.
function customEvent(name, detail) {
var evt = document.createEvent('Event');
evt.initEvent(name, true, true);
@ -7,7 +15,12 @@ function customEvent(name, detail) {
return evt;
}
// Add extra fields to a bounding box returned by `getBBox`. Specifically adds
// details about the box's axis points (used when positioning elements for
// display).
//
// - __box__ - Bounding box object to update. Attributes `ax`, `ax2`, and `ay`
// will be added if they are not already defined.
function normalizeBBox(box) {
return _.extend({
ax: box.x,
@ -16,6 +29,12 @@ function normalizeBBox(box) {
}, box);
}
// Positions a collection of items with their axis points aligned along a
// horizontal line. This leads to the items being spaced horizontally and
// effectively centered vertically.
//
// - __items__ - Array of items to be positioned
// - __options.padding__ - Number of pixels to leave between items
function spaceHorizontally(items, options) {
var verticalCenter = 0;
@ -23,6 +42,8 @@ function spaceHorizontally(items, options) {
padding: 0
});
// Set horizontal position of items with padding between them, and calculate
// where the axis points should be positioned vertically.
_.reduce(items, (offset, item) => {
var box;
@ -35,6 +56,7 @@ function spaceHorizontally(items, options) {
return offset + options.padding + box.width;
}, 0);
// Set vertical position of items to align their axis points.
for (var item of items) {
let box = normalizeBBox(item.getBBox());
@ -44,6 +66,10 @@ function spaceHorizontally(items, options) {
}
}
// Positions a collection of items centered horizontally in a vertical stack.
//
// - __items__ - Array of items to be positioned
// - __options.padding__ - Number of pixels to leave between items
function spaceVertically(items, options) {
var horizontalCenter = 0;
@ -51,6 +77,8 @@ function spaceVertically(items, options) {
padding: 0
});
// Set vertical position of items with padding between them, and calculate
// where the center of each item should be positioned horizontally.
_.reduce(items, (offset, item) => {
var box;
@ -64,6 +92,7 @@ function spaceVertically(items, options) {
return offset + options.padding + box.height;
}, 0);
// Set horizontal position of items to align their centers.
for (var item of items) {
item.transform(Snap.matrix()
.add(item.transform().localMatrix)
@ -71,16 +100,27 @@ function spaceVertically(items, options) {
}
}
// Creates a Promise that will be resolved after a specified delay.
//
// - __delay__ - Time in milliseconds to wait before resolving promise.
function wait(delay) {
return new Promise((resolve, reject) => {
setTimeout(resolve, delay);
});
}
// Creates a Promise that will be resolved after 0 milliseconds. This is used
// to create a short delay that allows the browser to address any pending tasks
// while the JavaScript VM is not active.
function tick() {
return wait(0);
}
// Re-throws an exception asynchronously. This is used to expose an exception
// that was created during a Promise operation to be handled by global error
// handlers (and to be displayed in the browser's debug console).
//
// - __error__ - Error/exception object to be re-thrown to the browser.
function exposeError(error) {
tick().then(() => {
throw error;