source: trip-planner-front/node_modules/qs/README.md@ 76712b2

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1# qs <sup>[![Version Badge][2]][1]</sup>
2
3[![Build Status][3]][4]
4[![dependency status][5]][6]
5[![dev dependency status][7]][8]
6[![License][license-image]][license-url]
7[![Downloads][downloads-image]][downloads-url]
8
9[![npm badge][11]][1]
10
11A querystring parsing and stringifying library with some added security.
12
13Lead Maintainer: [Jordan Harband](https://github.com/ljharb)
14
15The **qs** module was originally created and maintained by [TJ Holowaychuk](https://github.com/visionmedia/node-querystring).
16
17## Usage
18
19```javascript
20var qs = require('qs');
21var assert = require('assert');
22
23var obj = qs.parse('a=c');
24assert.deepEqual(obj, { a: 'c' });
25
26var str = qs.stringify(obj);
27assert.equal(str, 'a=c');
28```
29
30### Parsing Objects
31
32[](#preventEval)
33```javascript
34qs.parse(string, [options]);
35```
36
37**qs** allows you to create nested objects within your query strings, by surrounding the name of sub-keys with square brackets `[]`.
38For example, the string `'foo[bar]=baz'` converts to:
39
40```javascript
41assert.deepEqual(qs.parse('foo[bar]=baz'), {
42 foo: {
43 bar: 'baz'
44 }
45});
46```
47
48When using the `plainObjects` option the parsed value is returned as a null object, created via `Object.create(null)` and as such you should be aware that prototype methods will not exist on it and a user may set those names to whatever value they like:
49
50```javascript
51var nullObject = qs.parse('a[hasOwnProperty]=b', { plainObjects: true });
52assert.deepEqual(nullObject, { a: { hasOwnProperty: 'b' } });
53```
54
55By default parameters that would overwrite properties on the object prototype are ignored, if you wish to keep the data from those fields either use `plainObjects` as mentioned above, or set `allowPrototypes` to `true` which will allow user input to overwrite those properties. *WARNING* It is generally a bad idea to enable this option as it can cause problems when attempting to use the properties that have been overwritten. Always be careful with this option.
56
57```javascript
58var protoObject = qs.parse('a[hasOwnProperty]=b', { allowPrototypes: true });
59assert.deepEqual(protoObject, { a: { hasOwnProperty: 'b' } });
60```
61
62URI encoded strings work too:
63
64```javascript
65assert.deepEqual(qs.parse('a%5Bb%5D=c'), {
66 a: { b: 'c' }
67});
68```
69
70You can also nest your objects, like `'foo[bar][baz]=foobarbaz'`:
71
72```javascript
73assert.deepEqual(qs.parse('foo[bar][baz]=foobarbaz'), {
74 foo: {
75 bar: {
76 baz: 'foobarbaz'
77 }
78 }
79});
80```
81
82By default, when nesting objects **qs** will only parse up to 5 children deep. This means if you attempt to parse a string like
83`'a[b][c][d][e][f][g][h][i]=j'` your resulting object will be:
84
85```javascript
86var expected = {
87 a: {
88 b: {
89 c: {
90 d: {
91 e: {
92 f: {
93 '[g][h][i]': 'j'
94 }
95 }
96 }
97 }
98 }
99 }
100};
101var string = 'a[b][c][d][e][f][g][h][i]=j';
102assert.deepEqual(qs.parse(string), expected);
103```
104
105This depth can be overridden by passing a `depth` option to `qs.parse(string, [options])`:
106
107```javascript
108var deep = qs.parse('a[b][c][d][e][f][g][h][i]=j', { depth: 1 });
109assert.deepEqual(deep, { a: { b: { '[c][d][e][f][g][h][i]': 'j' } } });
110```
111
112The depth limit helps mitigate abuse when **qs** is used to parse user input, and it is recommended to keep it a reasonably small number.
113
114For similar reasons, by default **qs** will only parse up to 1000 parameters. This can be overridden by passing a `parameterLimit` option:
115
116```javascript
117var limited = qs.parse('a=b&c=d', { parameterLimit: 1 });
118assert.deepEqual(limited, { a: 'b' });
119```
120
121To bypass the leading question mark, use `ignoreQueryPrefix`:
122
123```javascript
124var prefixed = qs.parse('?a=b&c=d', { ignoreQueryPrefix: true });
125assert.deepEqual(prefixed, { a: 'b', c: 'd' });
126```
127
128An optional delimiter can also be passed:
129
130```javascript
131var delimited = qs.parse('a=b;c=d', { delimiter: ';' });
132assert.deepEqual(delimited, { a: 'b', c: 'd' });
133```
134
135Delimiters can be a regular expression too:
136
137```javascript
138var regexed = qs.parse('a=b;c=d,e=f', { delimiter: /[;,]/ });
139assert.deepEqual(regexed, { a: 'b', c: 'd', e: 'f' });
140```
141
142Option `allowDots` can be used to enable dot notation:
143
144```javascript
145var withDots = qs.parse('a.b=c', { allowDots: true });
146assert.deepEqual(withDots, { a: { b: 'c' } });
147```
148
149If you have to deal with legacy browsers or services, there's
150also support for decoding percent-encoded octets as iso-8859-1:
151
152```javascript
153var oldCharset = qs.parse('a=%A7', { charset: 'iso-8859-1' });
154assert.deepEqual(oldCharset, { a: '§' });
155```
156
157Some services add an initial `utf8=✓` value to forms so that old
158Internet Explorer versions are more likely to submit the form as
159utf-8. Additionally, the server can check the value against wrong
160encodings of the checkmark character and detect that a query string
161or `application/x-www-form-urlencoded` body was *not* sent as
162utf-8, eg. if the form had an `accept-charset` parameter or the
163containing page had a different character set.
164
165**qs** supports this mechanism via the `charsetSentinel` option.
166If specified, the `utf8` parameter will be omitted from the
167returned object. It will be used to switch to `iso-8859-1`/`utf-8`
168mode depending on how the checkmark is encoded.
169
170**Important**: When you specify both the `charset` option and the
171`charsetSentinel` option, the `charset` will be overridden when
172the request contains a `utf8` parameter from which the actual
173charset can be deduced. In that sense the `charset` will behave
174as the default charset rather than the authoritative charset.
175
176```javascript
177var detectedAsUtf8 = qs.parse('utf8=%E2%9C%93&a=%C3%B8', {
178 charset: 'iso-8859-1',
179 charsetSentinel: true
180});
181assert.deepEqual(detectedAsUtf8, { a: 'ø' });
182
183// Browsers encode the checkmark as &#10003; when submitting as iso-8859-1:
184var detectedAsIso8859_1 = qs.parse('utf8=%26%2310003%3B&a=%F8', {
185 charset: 'utf-8',
186 charsetSentinel: true
187});
188assert.deepEqual(detectedAsIso8859_1, { a: 'ø' });
189```
190
191If you want to decode the `&#...;` syntax to the actual character,
192you can specify the `interpretNumericEntities` option as well:
193
194```javascript
195var detectedAsIso8859_1 = qs.parse('a=%26%239786%3B', {
196 charset: 'iso-8859-1',
197 interpretNumericEntities: true
198});
199assert.deepEqual(detectedAsIso8859_1, { a: '☺' });
200```
201
202It also works when the charset has been detected in `charsetSentinel`
203mode.
204
205### Parsing Arrays
206
207**qs** can also parse arrays using a similar `[]` notation:
208
209```javascript
210var withArray = qs.parse('a[]=b&a[]=c');
211assert.deepEqual(withArray, { a: ['b', 'c'] });
212```
213
214You may specify an index as well:
215
216```javascript
217var withIndexes = qs.parse('a[1]=c&a[0]=b');
218assert.deepEqual(withIndexes, { a: ['b', 'c'] });
219```
220
221Note that the only difference between an index in an array and a key in an object is that the value between the brackets must be a number
222to create an array. When creating arrays with specific indices, **qs** will compact a sparse array to only the existing values preserving
223their order:
224
225```javascript
226var noSparse = qs.parse('a[1]=b&a[15]=c');
227assert.deepEqual(noSparse, { a: ['b', 'c'] });
228```
229
230Note that an empty string is also a value, and will be preserved:
231
232```javascript
233var withEmptyString = qs.parse('a[]=&a[]=b');
234assert.deepEqual(withEmptyString, { a: ['', 'b'] });
235
236var withIndexedEmptyString = qs.parse('a[0]=b&a[1]=&a[2]=c');
237assert.deepEqual(withIndexedEmptyString, { a: ['b', '', 'c'] });
238```
239
240**qs** will also limit specifying indices in an array to a maximum index of `20`. Any array members with an index of greater than `20` will
241instead be converted to an object with the index as the key. This is needed to handle cases when someone sent, for example, `a[999999999]` and it will take significant time to iterate over this huge array.
242
243```javascript
244var withMaxIndex = qs.parse('a[100]=b');
245assert.deepEqual(withMaxIndex, { a: { '100': 'b' } });
246```
247
248This limit can be overridden by passing an `arrayLimit` option:
249
250```javascript
251var withArrayLimit = qs.parse('a[1]=b', { arrayLimit: 0 });
252assert.deepEqual(withArrayLimit, { a: { '1': 'b' } });
253```
254
255To disable array parsing entirely, set `parseArrays` to `false`.
256
257```javascript
258var noParsingArrays = qs.parse('a[]=b', { parseArrays: false });
259assert.deepEqual(noParsingArrays, { a: { '0': 'b' } });
260```
261
262If you mix notations, **qs** will merge the two items into an object:
263
264```javascript
265var mixedNotation = qs.parse('a[0]=b&a[b]=c');
266assert.deepEqual(mixedNotation, { a: { '0': 'b', b: 'c' } });
267```
268
269You can also create arrays of objects:
270
271```javascript
272var arraysOfObjects = qs.parse('a[][b]=c');
273assert.deepEqual(arraysOfObjects, { a: [{ b: 'c' }] });
274```
275
276Some people use comma to join array, **qs** can parse it:
277```javascript
278var arraysOfObjects = qs.parse('a=b,c', { comma: true })
279assert.deepEqual(arraysOfObjects, { a: ['b', 'c'] })
280```
281(_this cannot convert nested objects, such as `a={b:1},{c:d}`_)
282
283### Stringifying
284
285[](#preventEval)
286```javascript
287qs.stringify(object, [options]);
288```
289
290When stringifying, **qs** by default URI encodes output. Objects are stringified as you would expect:
291
292```javascript
293assert.equal(qs.stringify({ a: 'b' }), 'a=b');
294assert.equal(qs.stringify({ a: { b: 'c' } }), 'a%5Bb%5D=c');
295```
296
297This encoding can be disabled by setting the `encode` option to `false`:
298
299```javascript
300var unencoded = qs.stringify({ a: { b: 'c' } }, { encode: false });
301assert.equal(unencoded, 'a[b]=c');
302```
303
304Encoding can be disabled for keys by setting the `encodeValuesOnly` option to `true`:
305```javascript
306var encodedValues = qs.stringify(
307 { a: 'b', c: ['d', 'e=f'], f: [['g'], ['h']] },
308 { encodeValuesOnly: true }
309);
310assert.equal(encodedValues,'a=b&c[0]=d&c[1]=e%3Df&f[0][0]=g&f[1][0]=h');
311```
312
313This encoding can also be replaced by a custom encoding method set as `encoder` option:
314
315```javascript
316var encoded = qs.stringify({ a: { b: 'c' } }, { encoder: function (str) {
317 // Passed in values `a`, `b`, `c`
318 return // Return encoded string
319}})
320```
321
322_(Note: the `encoder` option does not apply if `encode` is `false`)_
323
324Analogue to the `encoder` there is a `decoder` option for `parse` to override decoding of properties and values:
325
326```javascript
327var decoded = qs.parse('x=z', { decoder: function (str) {
328 // Passed in values `x`, `z`
329 return // Return decoded string
330}})
331```
332
333Examples beyond this point will be shown as though the output is not URI encoded for clarity. Please note that the return values in these cases *will* be URI encoded during real usage.
334
335When arrays are stringified, by default they are given explicit indices:
336
337```javascript
338qs.stringify({ a: ['b', 'c', 'd'] });
339// 'a[0]=b&a[1]=c&a[2]=d'
340```
341
342You may override this by setting the `indices` option to `false`:
343
344```javascript
345qs.stringify({ a: ['b', 'c', 'd'] }, { indices: false });
346// 'a=b&a=c&a=d'
347```
348
349You may use the `arrayFormat` option to specify the format of the output array:
350
351```javascript
352qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'indices' })
353// 'a[0]=b&a[1]=c'
354qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'brackets' })
355// 'a[]=b&a[]=c'
356qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'repeat' })
357// 'a=b&a=c'
358qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'comma' })
359// 'a=b,c'
360```
361
362When objects are stringified, by default they use bracket notation:
363
364```javascript
365qs.stringify({ a: { b: { c: 'd', e: 'f' } } });
366// 'a[b][c]=d&a[b][e]=f'
367```
368
369You may override this to use dot notation by setting the `allowDots` option to `true`:
370
371```javascript
372qs.stringify({ a: { b: { c: 'd', e: 'f' } } }, { allowDots: true });
373// 'a.b.c=d&a.b.e=f'
374```
375
376Empty strings and null values will omit the value, but the equals sign (=) remains in place:
377
378```javascript
379assert.equal(qs.stringify({ a: '' }), 'a=');
380```
381
382Key with no values (such as an empty object or array) will return nothing:
383
384```javascript
385assert.equal(qs.stringify({ a: [] }), '');
386assert.equal(qs.stringify({ a: {} }), '');
387assert.equal(qs.stringify({ a: [{}] }), '');
388assert.equal(qs.stringify({ a: { b: []} }), '');
389assert.equal(qs.stringify({ a: { b: {}} }), '');
390```
391
392Properties that are set to `undefined` will be omitted entirely:
393
394```javascript
395assert.equal(qs.stringify({ a: null, b: undefined }), 'a=');
396```
397
398The query string may optionally be prepended with a question mark:
399
400```javascript
401assert.equal(qs.stringify({ a: 'b', c: 'd' }, { addQueryPrefix: true }), '?a=b&c=d');
402```
403
404The delimiter may be overridden with stringify as well:
405
406```javascript
407assert.equal(qs.stringify({ a: 'b', c: 'd' }, { delimiter: ';' }), 'a=b;c=d');
408```
409
410If you only want to override the serialization of `Date` objects, you can provide a `serializeDate` option:
411
412```javascript
413var date = new Date(7);
414assert.equal(qs.stringify({ a: date }), 'a=1970-01-01T00:00:00.007Z'.replace(/:/g, '%3A'));
415assert.equal(
416 qs.stringify({ a: date }, { serializeDate: function (d) { return d.getTime(); } }),
417 'a=7'
418);
419```
420
421You may use the `sort` option to affect the order of parameter keys:
422
423```javascript
424function alphabeticalSort(a, b) {
425 return a.localeCompare(b);
426}
427assert.equal(qs.stringify({ a: 'c', z: 'y', b : 'f' }, { sort: alphabeticalSort }), 'a=c&b=f&z=y');
428```
429
430Finally, you can use the `filter` option to restrict which keys will be included in the stringified output.
431If you pass a function, it will be called for each key to obtain the replacement value. Otherwise, if you
432pass an array, it will be used to select properties and array indices for stringification:
433
434```javascript
435function filterFunc(prefix, value) {
436 if (prefix == 'b') {
437 // Return an `undefined` value to omit a property.
438 return;
439 }
440 if (prefix == 'e[f]') {
441 return value.getTime();
442 }
443 if (prefix == 'e[g][0]') {
444 return value * 2;
445 }
446 return value;
447}
448qs.stringify({ a: 'b', c: 'd', e: { f: new Date(123), g: [2] } }, { filter: filterFunc });
449// 'a=b&c=d&e[f]=123&e[g][0]=4'
450qs.stringify({ a: 'b', c: 'd', e: 'f' }, { filter: ['a', 'e'] });
451// 'a=b&e=f'
452qs.stringify({ a: ['b', 'c', 'd'], e: 'f' }, { filter: ['a', 0, 2] });
453// 'a[0]=b&a[2]=d'
454```
455
456### Handling of `null` values
457
458By default, `null` values are treated like empty strings:
459
460```javascript
461var withNull = qs.stringify({ a: null, b: '' });
462assert.equal(withNull, 'a=&b=');
463```
464
465Parsing does not distinguish between parameters with and without equal signs. Both are converted to empty strings.
466
467```javascript
468var equalsInsensitive = qs.parse('a&b=');
469assert.deepEqual(equalsInsensitive, { a: '', b: '' });
470```
471
472To distinguish between `null` values and empty strings use the `strictNullHandling` flag. In the result string the `null`
473values have no `=` sign:
474
475```javascript
476var strictNull = qs.stringify({ a: null, b: '' }, { strictNullHandling: true });
477assert.equal(strictNull, 'a&b=');
478```
479
480To parse values without `=` back to `null` use the `strictNullHandling` flag:
481
482```javascript
483var parsedStrictNull = qs.parse('a&b=', { strictNullHandling: true });
484assert.deepEqual(parsedStrictNull, { a: null, b: '' });
485```
486
487To completely skip rendering keys with `null` values, use the `skipNulls` flag:
488
489```javascript
490var nullsSkipped = qs.stringify({ a: 'b', c: null}, { skipNulls: true });
491assert.equal(nullsSkipped, 'a=b');
492```
493
494If you're communicating with legacy systems, you can switch to `iso-8859-1`
495using the `charset` option:
496
497```javascript
498var iso = qs.stringify({ æ: 'æ' }, { charset: 'iso-8859-1' });
499assert.equal(iso, '%E6=%E6');
500```
501
502Characters that don't exist in `iso-8859-1` will be converted to numeric
503entities, similar to what browsers do:
504
505```javascript
506var numeric = qs.stringify({ a: '☺' }, { charset: 'iso-8859-1' });
507assert.equal(numeric, 'a=%26%239786%3B');
508```
509
510You can use the `charsetSentinel` option to announce the character by
511including an `utf8=✓` parameter with the proper encoding if the checkmark,
512similar to what Ruby on Rails and others do when submitting forms.
513
514```javascript
515var sentinel = qs.stringify({ a: '☺' }, { charsetSentinel: true });
516assert.equal(sentinel, 'utf8=%E2%9C%93&a=%E2%98%BA');
517
518var isoSentinel = qs.stringify({ a: 'æ' }, { charsetSentinel: true, charset: 'iso-8859-1' });
519assert.equal(isoSentinel, 'utf8=%26%2310003%3B&a=%E6');
520```
521
522### Dealing with special character sets
523
524By default the encoding and decoding of characters is done in `utf-8`,
525and `iso-8859-1` support is also built in via the `charset` parameter.
526
527If you wish to encode querystrings to a different character set (i.e.
528[Shift JIS](https://en.wikipedia.org/wiki/Shift_JIS)) you can use the
529[`qs-iconv`](https://github.com/martinheidegger/qs-iconv) library:
530
531```javascript
532var encoder = require('qs-iconv/encoder')('shift_jis');
533var shiftJISEncoded = qs.stringify({ a: 'こんにちは!' }, { encoder: encoder });
534assert.equal(shiftJISEncoded, 'a=%82%B1%82%F1%82%C9%82%BF%82%CD%81I');
535```
536
537This also works for decoding of query strings:
538
539```javascript
540var decoder = require('qs-iconv/decoder')('shift_jis');
541var obj = qs.parse('a=%82%B1%82%F1%82%C9%82%BF%82%CD%81I', { decoder: decoder });
542assert.deepEqual(obj, { a: 'こんにちは!' });
543```
544
545### RFC 3986 and RFC 1738 space encoding
546
547RFC3986 used as default option and encodes ' ' to *%20* which is backward compatible.
548In the same time, output can be stringified as per RFC1738 with ' ' equal to '+'.
549
550```
551assert.equal(qs.stringify({ a: 'b c' }), 'a=b%20c');
552assert.equal(qs.stringify({ a: 'b c' }, { format : 'RFC3986' }), 'a=b%20c');
553assert.equal(qs.stringify({ a: 'b c' }, { format : 'RFC1738' }), 'a=b+c');
554```
555
556[1]: https://npmjs.org/package/qs
557[2]: http://versionbadg.es/ljharb/qs.svg
558[3]: https://api.travis-ci.org/ljharb/qs.svg
559[4]: https://travis-ci.org/ljharb/qs
560[5]: https://david-dm.org/ljharb/qs.svg
561[6]: https://david-dm.org/ljharb/qs
562[7]: https://david-dm.org/ljharb/qs/dev-status.svg
563[8]: https://david-dm.org/ljharb/qs?type=dev
564[9]: https://ci.testling.com/ljharb/qs.png
565[10]: https://ci.testling.com/ljharb/qs
566[11]: https://nodei.co/npm/qs.png?downloads=true&stars=true
567[license-image]: http://img.shields.io/npm/l/qs.svg
568[license-url]: LICENSE
569[downloads-image]: http://img.shields.io/npm/dm/qs.svg
570[downloads-url]: http://npm-stat.com/charts.html?package=qs
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