metro/formatBanner.js

109 lines
3.3 KiB
JavaScript
Raw Normal View History

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
'use strict';
var _ = require('underscore');
var wordwrap = require('wordwrap');
var HORIZONTAL_LINE = '\u2500';
var VERTICAL_LINE = '\u2502';
var TOP_LEFT = '\u250c';
var TOP_RIGHT = '\u2510';
var BOTTOM_LEFT = '\u2514';
var BOTTOM_RIGHT = '\u2518';
/**
* Prints a banner with a border around it containing the given message. The
* following options are supported:
*
* type Options = {
* // A function to apply to each line of text to decorate it
* chalkFunction: (string: message) => string;
* // The total width (max line length) of the banner, including margin and
* // padding (default = 80)
* width: number;
* // How much leading space to prepend to each line (default = 0)
* marginLeft: number;
* // How much trailing space to append to each line (default = 0)
* marginRight: number;
* // Space between the top banner border and the text (default = 0)
* paddingTop: number;
* // Space between the bottom banner border and the text (default = 0)
* paddingBottom: number;
* // Space between the left banner border and the text (default = 2)
* paddingLeft: number;
* // Space between the right banner border and the text (default = 2)
* paddingRight: number;
* };
*/
function formatBanner(message, options) {
options = options || {};
_.defaults(options, {
chalkFunction: _.identity,
width: 80,
marginLeft: 0,
marginRight: 0,
paddingTop: 0,
paddingBottom: 0,
paddingLeft: 2,
paddingRight: 2,
});
var width = options.width;
var marginLeft = options.marginLeft;
var marginRight = options.marginRight;
var paddingTop = options.paddingTop;
var paddingBottom = options.paddingBottom;
var paddingLeft = options.paddingLeft;
var paddingRight = options.paddingRight;
var horizSpacing = marginLeft + paddingLeft + paddingRight + marginRight;
// 2 for the banner borders
var maxLineWidth = width - horizSpacing - 2;
var wrap = wordwrap(maxLineWidth);
var body = wrap(message);
var left = spaces(marginLeft) + VERTICAL_LINE + spaces(paddingLeft);
var right = spaces(paddingRight) + VERTICAL_LINE + spaces(marginRight);
var bodyLines = _.flatten([
arrayOf('', paddingTop),
body.split('\n'),
arrayOf('', paddingBottom),
]).map(function(line) {
var padding = spaces(Math.max(0, maxLineWidth - line.length));
return left + options.chalkFunction(line) + padding + right;
});
var horizontalBorderLine = repeatString(
HORIZONTAL_LINE,
width - marginLeft - marginRight - 2
);
var top = spaces(marginLeft) + TOP_LEFT + horizontalBorderLine + TOP_RIGHT +
spaces(marginRight);
var bottom = spaces(marginLeft) + BOTTOM_LEFT + horizontalBorderLine +
BOTTOM_RIGHT + spaces(marginRight);
return _.flatten([top, bodyLines, bottom]).join('\n');
}
function spaces(number) {
return repeatString(' ', number);
}
function repeatString(string, number) {
return new Array(number + 1).join(string);
}
function arrayOf(value, number) {
return _.range(number).map(function() {
return value;
});
}
module.exports = formatBanner;