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Use a WeakMap for private properties #42

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Merged
merged 7 commits into from
Jun 6, 2020
Merged

Use a WeakMap for private properties #42

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1a8e0f4
options.buffer isn't a valid option
jimmywarting Jun 5, 2020
3b21cb4
use default arguments
jimmywarting Jun 5, 2020
a386ab7
concat perf
jimmywarting Jun 5, 2020
802c03b
truly private internal properties
jimmywarting Jun 5, 2020
23fc22c
removed spaces
jimmywarting Jun 5, 2020
5c6b31f
100% test coverage
jimmywarting Jun 5, 2020
86f69c5
lint fix
jimmywarting Jun 5, 2020
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93 changes: 41 additions & 52 deletions index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -3,74 +3,64 @@

const {Readable: ReadableStream} = require('stream');

const BUFFER = Symbol('buffer');
const TYPE = Symbol('type');
const wm = new WeakMap();

class Blob {
constructor(...args) {
this[TYPE] = '';

const blobParts = args[0];
const options = args[1];

constructor(blobParts = [], options = {type: ''}) {
const buffers = [];
/* eslint-disable-next-line no-unused-vars */
let size = 0;

if (blobParts) {
blobParts.forEach(element => {
let buffer;
if (element instanceof Buffer) {
buffer = element;
} else if (ArrayBuffer.isView(element)) {
buffer = Buffer.from(element.buffer, element.byteOffset, element.byteLength);
} else if (element instanceof ArrayBuffer) {
buffer = Buffer.from(element);
} else if (element instanceof Blob) {
buffer = element[BUFFER];
} else {
buffer = Buffer.from(typeof element === 'string' ? element : String(element));
}

size += buffer.length;
buffers.push(buffer);
});
}

this[BUFFER] = Buffer.concat(buffers);

const type = options && options.type !== undefined && String(options.type).toLowerCase();
if (type && !/[^\u0020-\u007E]/.test(type)) {
this[TYPE] = type;
}

if (options && Buffer.isBuffer(options.buffer)) {
this[BUFFER] = options.buffer;
}
blobParts.forEach(element => {
let buffer;
if (element instanceof Buffer) {
buffer = element;
} else if (ArrayBuffer.isView(element)) {
buffer = Buffer.from(element.buffer, element.byteOffset, element.byteLength);
} else if (element instanceof ArrayBuffer) {
buffer = Buffer.from(element);
} else if (element instanceof Blob) {
buffer = wm.get(element).buffer;
} else {
buffer = Buffer.from(typeof element === 'string' ? element : String(element));
}

size += buffer.length;
buffers.push(buffer);
});

const buffer = Buffer.concat(buffers, size);

const type = options.type === undefined ? '' : String(options.type).toLowerCase();

wm.set(this, {
type: /[^\u0020-\u007E]/.test(type) ? '' : type,
size,
buffer
});
}

get size() {
return this[BUFFER].length;
return wm.get(this).size;
}

get type() {
return this[TYPE];
return wm.get(this).type;
}

text() {
return Promise.resolve(this[BUFFER].toString());
return Promise.resolve(wm.get(this).buffer.toString());
}

arrayBuffer() {
const buf = this[BUFFER];
const buf = wm.get(this).buffer;
const ab = buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
return Promise.resolve(ab);
}

stream() {
const readable = new ReadableStream();
readable._read = () => { };
readable.push(this[BUFFER]);
readable.push(wm.get(this).buffer);
readable.push(null);
return readable;
}
Expand All @@ -88,30 +78,29 @@ class Blob {
let relativeEnd;

if (start === undefined) {
relativeStart = 0;
relativeStart = 0; //
} else if (start < 0) {
relativeStart = Math.max(size + start, 0);
relativeStart = Math.max(size + start, 0); //
} else {
relativeStart = Math.min(start, size);
}

if (end === undefined) {
relativeEnd = size;
relativeEnd = size; //
} else if (end < 0) {
relativeEnd = Math.max(size + end, 0);
relativeEnd = Math.max(size + end, 0); //
} else {
relativeEnd = Math.min(end, size);
}

const span = Math.max(relativeEnd - relativeStart, 0);

const buffer = this[BUFFER];
const slicedBuffer = buffer.slice(
const slicedBuffer = wm.get(this).buffer.slice(
relativeStart,
relativeStart + span
);
const blob = new Blob([], {type: args[2]});
blob[BUFFER] = slicedBuffer;
const _ = wm.get(blob);
_.buffer = slicedBuffer;
return blob;
}
}
Expand Down
67 changes: 59 additions & 8 deletions test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -3,25 +3,60 @@ const Blob = require('.');
const getStream = require('get-stream');
const {Response} = require('node-fetch');

test('Blob ctor', t => {
test('new Blob()', t => {
const blob = new Blob(); // eslint-disable-line no-unused-vars
t.pass();
});

test('new Blob(parts)', t => {
const data = 'a=1';
const blob = new Blob([data]); // eslint-disable-line no-unused-vars
t.pass();
});

test('Blob ctor parts', async t => {
const parts = [
'a',
new Uint8Array([98]),
new Uint16Array([25699]),
new Uint8Array([101]).buffer,
Buffer.from('f'),
new Blob(['g']),
{}
];

const blob = new Blob(parts);
t.is(await blob.text(), 'abcdefg[object Object]');
});

test('Blob size', t => {
const data = 'a=1';
const blob = new Blob([data]);
t.is(blob.size, data.length);
});

test('Blob type', t => {
const data = 'a=1';
const type = 'text/plain';
const blob = new Blob([data], {type});
const blob = new Blob([], {type});
t.is(blob.type, type);
});

test('Blob slice type', t => {
const type = 'text/plain';
const blob = new Blob().slice(0, 0, type);
t.is(blob.type, type);
});

test('invalid Blob type', t => {
const blob = new Blob([], {type: '\u001Ftext/plain'});
t.is(blob.type, '');
});

test('invalid Blob slice type', t => {
const blob = new Blob().slice(0, 0, '\u001Ftext/plain');
t.is(blob.type, '');
});

test('Blob text()', async t => {
const data = 'a=1';
const type = 'text/plain';
Expand Down Expand Up @@ -55,11 +90,27 @@ test('Blob toString()', t => {
});

test('Blob slice()', async t => {
const data = 'a=1';
const type = 'text/plain';
const blob = new Blob([data], {type});
const blob2 = blob.slice(0, 1);
t.is(await blob2.text(), data.slice(0, 1));
const data = 'abcdefgh';
const blob = new Blob([data]).slice();
t.is(await blob.text(), data);
});

test('Blob slice(0, 1)', async t => {
const data = 'abcdefgh';
const blob = new Blob([data]).slice(0, 1);
t.is(await blob.text(), 'a');
});

test('Blob slice(-1)', async t => {
const data = 'abcdefgh';
const blob = new Blob([data]).slice(-1);
t.is(await blob.text(), 'h');
});

test('Blob slice(0, -1)', async t => {
const data = 'abcdefgh';
const blob = new Blob([data]).slice(0, -1);
t.is(await blob.text(), 'abcdefg');
});

test('Blob works with node-fetch Response.blob()', async t => {
Expand Down