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[Docs] Add evalmd, fix broken examples in README, and ensure all ex…
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…amples have assertions.
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ljharb committed Jan 17, 2016
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144 changes: 74 additions & 70 deletions README.md
Expand Up @@ -12,13 +12,18 @@ The **qs** module was originally created and maintained by [TJ Holowaychuk](http

```javascript
var qs = require('qs');
var assert = require('assert');

var obj = qs.parse('a=c'); // { a: 'c' }
var str = qs.stringify(obj); // 'a=c'
var obj = qs.parse('a=c');
assert.deepEqual(obj, { a: 'c' });

var str = qs.stringify(obj);
assert.equal(str, 'a=c');
```

### Parsing Objects

[](#preventEval)
```javascript
qs.parse(string, [options]);
```
Expand All @@ -27,51 +32,52 @@ qs.parse(string, [options]);
For example, the string `'foo[bar]=baz'` converts to:

```javascript
{
assert.deepEqual(qs.parse('foo[bar]=baz'), {
foo: {
bar: 'baz'
}
}
});
```

When using the `plainObjects` option the parsed value is returned as a plain 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:

```javascript
qs.parse('a.hasOwnProperty=b', { plainObjects: true });
// { a: { hasOwnProperty: 'b' } }
var plainObject = qs.parse('a[hasOwnProperty]=b', { plainObjects: true });
assert.deepEqual(plainObject, { a: { hasOwnProperty: 'b' } });
```

By 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.

```javascript
qs.parse('a.hasOwnProperty=b', { allowPrototypes: true });
// { a: { hasOwnProperty: 'b' } }
var protoObject = qs.parse('a[hasOwnProperty]=b', { allowPrototypes: true });
assert.deepEqual(protoObject, { a: { hasOwnProperty: 'b' } });
```

URI encoded strings work too:

```javascript
qs.parse('a%5Bb%5D=c');
// { a: { b: 'c' } }
assert.deepEqual(qs.parse('a%5Bb%5D=c'), {
a: { b: 'c' }
});
```

You can also nest your objects, like `'foo[bar][baz]=foobarbaz'`:

```javascript
{
assert.deepEqual(qs.parse('foo[bar][baz]=foobarbaz'), {
foo: {
bar: {
baz: 'foobarbaz'
}
}
}
});
```

By default, when nesting objects **qs** will only parse up to 5 children deep. This means if you attempt to parse a string like
`'a[b][c][d][e][f][g][h][i]=j'` your resulting object will be:

```javascript
{
var expected = {
a: {
b: {
c: {
Expand All @@ -85,136 +91,138 @@ By default, when nesting objects **qs** will only parse up to 5 children deep. T
}
}
}
}
};
var string = 'a[b][c][d][e][f][g][h][i]=j';
assert.deepEqual(qs.parse(string), expected);
```

This depth can be overridden by passing a `depth` option to `qs.parse(string, [options])`:

```javascript
qs.parse('a[b][c][d][e][f][g][h][i]=j', { depth: 1 });
// { a: { b: { '[c][d][e][f][g][h][i]': 'j' } } }
var deep = qs.parse('a[b][c][d][e][f][g][h][i]=j', { depth: 1 });
assert.deepEqual(deep, { a: { b: { '[c][d][e][f][g][h][i]': 'j' } } });
```

The depth limit helps mitigate abuse when **qs** is used to parse user input, and it is recommended to keep it a reasonably small number.

For similar reasons, by default **qs** will only parse up to 1000 parameters. This can be overridden by passing a `parameterLimit` option:

```javascript
qs.parse('a=b&c=d', { parameterLimit: 1 });
// { a: 'b' }
var limited = qs.parse('a=b&c=d', { parameterLimit: 1 });
assert.deepEqual(limited, { a: 'b' });
```

An optional delimiter can also be passed:

```javascript
qs.parse('a=b;c=d', { delimiter: ';' });
// { a: 'b', c: 'd' }
var delimited = qs.parse('a=b;c=d', { delimiter: ';' });
assert.deepEqual(delimited, { a: 'b', c: 'd' });
```

Delimiters can be a regular expression too:

```javascript
qs.parse('a=b;c=d,e=f', { delimiter: /[;,]/ });
// { a: 'b', c: 'd', e: 'f' }
var regexed = qs.parse('a=b;c=d,e=f', { delimiter: /[;,]/ });
assert.deepEqual(regexed, { a: 'b', c: 'd', e: 'f' });
```

Option `allowDots` can be used to enable dot notation:

```javascript
qs.parse('a.b=c', { allowDots: true });
// { a: { b: 'c' } }
var withDots = qs.parse('a.b=c', { allowDots: true });
assert.deepEqual(withDots, { a: { b: 'c' } });
```

### Parsing Arrays

**qs** can also parse arrays using a similar `[]` notation:

```javascript
qs.parse('a[]=b&a[]=c');
// { a: ['b', 'c'] }
var withArray = qs.parse('a[]=b&a[]=c');
assert.deepEqual(withArray, { a: ['b', 'c'] });
```

You may specify an index as well:

```javascript
qs.parse('a[1]=c&a[0]=b');
// { a: ['b', 'c'] }
var withIndexes = qs.parse('a[1]=c&a[0]=b');
assert.deepEqual(withIndexes, { a: ['b', 'c'] });
```

Note 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
to create an array. When creating arrays with specific indices, **qs** will compact a sparse array to only the existing values preserving
their order:

```javascript
qs.parse('a[1]=b&a[15]=c');
// { a: ['b', 'c'] }
var noSparse = qs.parse('a[1]=b&a[15]=c');
assert.deepEqual(noSparse, { a: ['b', 'c'] });
```

Note that an empty string is also a value, and will be preserved:

```javascript
qs.parse('a[]=&a[]=b');
// { a: ['', 'b'] }
qs.parse('a[0]=b&a[1]=&a[2]=c');
// { a: ['b', '', 'c'] }
var withEmptyString = qs.parse('a[]=&a[]=b');
assert.deepEqual(withEmptyString, { a: ['', 'b'] });

var withIndexedEmptyString = qs.parse('a[0]=b&a[1]=&a[2]=c');
assert.deepEqual(withIndexedEmptyString, { a: ['b', '', 'c'] });
```

**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
instead be converted to an object with the index as the key:

```javascript
qs.parse('a[100]=b');
// { a: { '100': 'b' } }
var withMaxIndex = qs.parse('a[100]=b');
assert.deepEqual(withMaxIndex, { a: { '100': 'b' } });
```

This limit can be overridden by passing an `arrayLimit` option:

```javascript
qs.parse('a[1]=b', { arrayLimit: 0 });
// { a: { '1': 'b' } }
var withArrayLimit = qs.parse('a[1]=b', { arrayLimit: 0 });
assert.deepEqual(withArrayLimit, { a: { '1': 'b' } });
```

To disable array parsing entirely, set `parseArrays` to `false`.

```javascript
qs.parse('a[]=b', { parseArrays: false });
// { a: { '0': 'b' } }
var noParsingArrays = qs.parse('a[]=b', { parseArrays: false });
assert.deepEqual(noParsingArrays, { a: { '0': 'b' } });
```

If you mix notations, **qs** will merge the two items into an object:

```javascript
qs.parse('a[0]=b&a[b]=c');
// { a: { '0': 'b', b: 'c' } }
var mixedNotation = qs.parse('a[0]=b&a[b]=c');
assert.deepEqual(mixedNotation, { a: { '0': 'b', b: 'c' } });
```

You can also create arrays of objects:

```javascript
qs.parse('a[][b]=c');
// { a: [{ b: 'c' }] }
var arraysOfObjects = qs.parse('a[][b]=c');
assert.deepEqual(arraysOfObjects, { a: [{ b: 'c' }] });
```

### Stringifying

[](#preventEval)
```javascript
qs.stringify(object, [options]);
```

When stringifying, **qs** by default URI encodes output. Objects are stringified as you would expect:

```javascript
qs.stringify({ a: 'b' });
// 'a=b'
qs.stringify({ a: { b: 'c' } });
// 'a%5Bb%5D=c'
assert.equal(qs.stringify({ a: 'b' }), 'a=b');
assert.equal(qs.stringify({ a: { b: 'c' } }), 'a%5Bb%5D=c');
```

This encoding can be disabled by setting the `encode` option to `false`:

```javascript
qs.stringify({ a: { b: 'c' } }, { encode: false });
// 'a[b]=c'
var unencoded = qs.stringify({ a: { b: 'c' } }, { encode: false });
assert.equal(unencoded, 'a[b]=c');
```

Examples 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.
Expand Down Expand Up @@ -247,22 +255,19 @@ qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'repeat' })
Empty strings and null values will omit the value, but the equals sign (=) remains in place:

```javascript
qs.stringify({ a: '' });
// 'a='
assert.equal(qs.stringify({ a: '' }), 'a=');
```

Properties that are set to `undefined` will be omitted entirely:

```javascript
qs.stringify({ a: null, b: undefined });
// 'a='
assert.equal(qs.stringify({ a: null, b: undefined }), 'a=');
```

The delimiter may be overridden with stringify as well:

```javascript
qs.stringify({ a: 'b', c: 'd' }, { delimiter: ';' });
// 'a=b;c=d'
assert.equal(qs.stringify({ a: 'b', c: 'd' }, { delimiter: ';' }), 'a=b;c=d');
```

Finally, you can use the `filter` option to restrict which keys will be included in the stringified output.
Expand All @@ -283,11 +288,11 @@ function filterFunc(prefix, value) {
}
return value;
}
qs.stringify({ a: 'b', c: 'd', e: { f: new Date(123), g: [2] } }, { filter: filterFunc })
qs.stringify({ a: 'b', c: 'd', e: { f: new Date(123), g: [2] } }, { filter: filterFunc });
// 'a=b&c=d&e[f]=123&e[g][0]=4'
qs.stringify({ a: 'b', c: 'd', e: 'f' }, { filter: ['a', 'e'] })
qs.stringify({ a: 'b', c: 'd', e: 'f' }, { filter: ['a', 'e'] });
// 'a=b&e=f'
qs.stringify({ a: ['b', 'c', 'd'], e: 'f' }, { filter: ['a', 0, 2] })
qs.stringify({ a: ['b', 'c', 'd'], e: 'f' }, { filter: ['a', 0, 2] });
// 'a[0]=b&a[2]=d'
```

Expand All @@ -296,36 +301,35 @@ qs.stringify({ a: ['b', 'c', 'd'], e: 'f' }, { filter: ['a', 0, 2] })
By default, `null` values are treated like empty strings:

```javascript
qs.stringify({ a: null, b: '' });
// 'a=&b='
var withNull = qs.stringify({ a: null, b: '' });
assert.equal(withNull, 'a=&b=');
```

Parsing does not distinguish between parameters with and without equal signs. Both are converted to empty strings.

```javascript
qs.parse('a&b=')
// { a: '', b: '' }
var equalsInsensitive = qs.parse('a&b=');
assert.deepEqual(equalsInsensitive, { a: '', b: '' });
```

To distinguish between `null` values and empty strings use the `strictNullHandling` flag. In the result string the `null`
values have no `=` sign:

```javascript
qs.stringify({ a: null, b: '' }, { strictNullHandling: true });
// 'a&b='
var strictNull = qs.stringify({ a: null, b: '' }, { strictNullHandling: true });
assert.equal(strictNull, 'a&b=');
```

To parse values without `=` back to `null` use the `strictNullHandling` flag:

```javascript
qs.parse('a&b=', { strictNullHandling: true });
// { a: null, b: '' }

var parsedStrictNull = qs.parse('a&b=', { strictNullHandling: true });
assert.deepEqual(parsedStrictNull, { a: null, b: '' });
```

To completely skip rendering keys with `null` values, use the `skipNulls` flag:

```javascript
qs.stringify({ a: 'b', c: null}, { skipNulls: true })
// 'a=b'
var nullsSkipped = qs.stringify({ a: 'b', c: null}, { skipNulls: true });
assert.equal(nullsSkipped, 'a=b');
```
8 changes: 5 additions & 3 deletions package.json
Expand Up @@ -30,11 +30,13 @@
"mkdirp": "^0.5.1",
"eslint": "^1.10.3",
"@ljharb/eslint-config": "^1.6.1",
"parallelshell": "^2.0.0"
"parallelshell": "^2.0.0",
"evalmd": "^0.0.16"
},
"scripts": {
"test": "parallelshell 'npm run lint' 'npm run coverage'",
"tests-only": "node test",
"test": "parallelshell 'npm run readme' 'npm run lint' 'npm run coverage'",
"tests-only": "parallelshell 'npm run readme' 'node test'",
"readme": "evalmd README.md",
"lint": "eslint lib/*.js text/*.js",
"coverage": "covert test",
"dist": "mkdirp dist && browserify --standalone Qs lib/index.js > dist/qs.js",
Expand Down

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