peter-generator
Version:
A simple thumbnail generator for JS.
124 lines (117 loc) • 5.02 kB
JavaScript
import * as _sharp from 'sharp';
/*! *****************************************************************************
Copyright (c) Microsoft Corporation. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use
this file except in compliance with the License. You may obtain a copy of the
License at http://www.apache.org/licenses/LICENSE-2.0
THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
MERCHANTABLITY OR NON-INFRINGEMENT.
See the Apache Version 2.0 License for specific language governing permissions
and limitations under the License.
***************************************************************************** */
var __assign = function() {
__assign = Object.assign || function __assign(t) {
for (var s, i = 1, n = arguments.length; i < n; i++) {
s = arguments[i];
for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p)) t[p] = s[p];
}
return t;
};
return __assign.apply(this, arguments);
};
var sharp = _sharp;
var defaultOpts = {
maxAttempts: 5,
maxWidth: 70,
sizeLimit: '100kB',
};
var ThumbnailGenerator = /** @class */ (function () {
function ThumbnailGenerator(opts) {
if (opts === void 0) { opts = {}; }
try {
this.checkPropsType(opts);
}
catch (e) {
console.error(e);
}
var mergedOpts = __assign({}, defaultOpts, opts);
this.maxAttempts = mergedOpts.maxAttempts;
this.maxWidth = mergedOpts.maxWidth;
this.sizeLimit = this.harmonizeByteSize(mergedOpts.sizeLimit);
}
ThumbnailGenerator.prototype.checkPropsType = function (opts) {
if (opts.maxWidth && typeof opts.maxWidth !== 'number') {
throw new Error('The maxWidth option should be of type number');
}
if (opts.sizeLimit && typeof opts.sizeLimit !== 'string' && typeof opts.sizeLimit !== 'number') {
throw new Error('The sizeLimit option should be of type string or number');
}
if (opts.maxAttempts && typeof opts.maxAttempts !== 'number') {
throw new Error('The maxAttempts option should be of type number');
}
};
ThumbnailGenerator.prototype.harmonizeByteSize = function (size) {
if (typeof size === 'number') {
return Math.floor(size);
}
var match = size.trim().match(/(-?\d*(?:\.\d+)?)\s*(\D*)/);
if (!match[1]) {
throw new Error('The numerical value of limit is missing');
}
if (match[2] && !match[2].match(/^(kB|MB|GB)$/i)) {
throw new Error('The unit value of limit is not valid (expected: kB, MB, GB)');
}
var value = parseInt(match[1], 10);
return Math.floor(match[2].toLowerCase() === 'gb' ?
value * 1073741824
:
match[2].toLowerCase() === 'mb' ?
value * 1048576
:
match[2].toLowerCase() === 'kb' ?
value * 1024
:
value);
};
ThumbnailGenerator.prototype.resize = function (img, opts) {
var _this = this;
img.metadata()
.then(function (_a) {
var height = _a.height, size = _a.size, width = _a.width;
if (size <= _this.sizeLimit) {
img.toBuffer()
.then(opts.onSuccess)
.catch(opts.onFail);
}
else if (opts.attemptN && opts.attemptN > _this.maxAttempts) {
opts.onFail('Number of attempts exceeded, failed to generate thumbnail');
}
else {
var nextWidth_1 = opts.width || _this.maxWidth;
return img.resize(Math.floor(nextWidth_1), Math.floor(nextWidth_1 / (opts.ratio || width / height)))
.toBuffer()
.then(function (data) {
_this.resize(sharp(data), __assign({}, opts, { attemptN: opts.attemptN ? opts.attemptN + 1 : 1, width: nextWidth_1 / 1.5 }));
});
}
})
.catch(opts.onFail);
};
ThumbnailGenerator.prototype.generate = function (input) {
var _this = this;
if (!Buffer.isBuffer(input)) {
throw new Error('The generate method expects an input of type Buffer');
}
var img = sharp(input);
return new Promise(function (resolve, reject) {
_this.resize(img, {
onSuccess: resolve,
onFail: reject,
});
});
};
return ThumbnailGenerator;
}());
export { ThumbnailGenerator };