Develop Reference

JavaScript - Function for finding text within a string

I have a function that I use to pass over a table field name and its value. Depending on the name of the field, it either returns the contents as a link or it does not.
// Given a field name, check to see if its in our output. If so, return the formatted link
function createLink(field, val) {
var output = {
'ntid': 'https://web.internal/profile/' + val,
'email': 'mailTo:' + val
};
var i, key, keys = Object.keys(output);
for ( i = 0; i < keys.length; ++i ) {
key = keys[i];
if(field.toLowerCase() == key){
return ''+val+'';
}
}
return val;
}
Usage:
createLink('email', 'bob#stuff.com')
// returns bob#stuff.com
This also works for NTID. The issue I am having though is there are some field names that contain my values in the output such as Sup Email or Sup NTID and those are not transformed correctly.
Expected Result:
createLink('sup email', 'bob2#stuff2.com')
// returns bob#stuff.com
The Question:
How can I tweak my function to see if my field exists in the output array at all, even if it's not an exact match?

Change your function to
function createLink(field, val) {
var output = {
'ntid': 'https://web.internal/profile/' + val,
'email': 'mailTo:' + val
};
var i, key, keys = Object.keys(output);
for (i = 0; i < keys.length; ++i) {
key = keys[i];
if ((field.toLowerCase()).includes(key)) {
return '' + val + '';
}
}
return val;
}
console.log(createLink('sup email', 'bob2#stuff2.com') )
Notice the code if ((field.toLowerCase()).includes(key)) {
This will check for your key substring in the string

What you're implementing is the Strategy Pattern. The Strategy Pattern relies on some form of behaviour-switching depending on the inputs to the method. In your case, that switching is based on the first argument.
What you don't want to do is what your questions asks how to do. You don't want to assume every field name in your application which contains "email" or some other string is guaranteed to be an email address, handled by the same strategy.
Create a table of field names and strategies to use for the display of each of these fields; and use an "enum-ish" object as the definition of the strategies.
function create_link(field, val) {
const strategy = create_link.Field_Strategies[field];
if (typeof strategy === 'undefined') {
console.log("Using default strategy");
return val;
}
console.log("Using " + strategy);
switch (strategy) {
case create_link.Strategies.EMAIL:
return '' + val + '';
case create_link.Strategies.NTID:
return '<a href="https://web.internal/profile/' +
val + '" target="_blank">' + val + '</a>';
case create_link.Strategies.SOME_FIELD:
return '<a href="http://example.com/some/path/' +
encodeURIComponent(val) +
'" target="_blank">' + val + '</a>';
}
}
create_link.Strategies = {
EMAIL: "email strategy",
NTID: "ntid strategy",
SOME_FIELD: "somefield strategy"
};
create_link.Field_Strategies = {
"Sup email": create_link.Strategies.EMAIL,
"E-mail": create_link.Strategies.EMAIL,
"Email": create_link.Strategies.EMAIL,
"NTID": create_link.Strategies.NTID,
"Foobar baz": create_link.Strategies.SOME_FIELD
};
console.log(create_link("foo","foofoofoo"));
console.log(create_link("Sup email","supervisor#example.com"));
console.log(create_link("E-mail","foo#example.com"));
console.log(create_link("Email","bar#example.com"));
console.log(create_link("NTID","10983409509734"));
console.log(create_link("Foobar baz","Aleph null"));

You could use String.prototype.indexOf.
The indexOf() method returns the index within the calling String object of the first occurrence of the specified value...Returns -1 if the value is not found.
So your code would then look like:
// Given a field name, check to see if its in our output. If so, return the formatted link
function createLink(field, val) {
var output = {
'ntid': 'https://web.internal/profile/' + val,
'email': 'mailTo:' + val
};
var i, key, keys = Object.keys(output);
for ( i = 0; i < keys.length; ++i ) {
key = keys[i];
if(field.toLowerCase().indexOf(key) >= 0){ //CHANGE HERE
return ''+val+'';
}
}
return val;
}

Recursively pass through Json to get all values for a specific key

I have a json object which looks like this:
var testJ = {"ROOT":{
dir : 'app',
files : [
'index.html',
{
dir : 'php',
files: [
'a.php',
{
dir : 'extras',
files : [
'a.js',
'b.js'
]
}
]
}
]
}};
I need to extract all the files and append into an array (index.html,a.php,a.js..etc)
For this I wrote a javascript code as follows:
var arr=[];
function scan(obj,append)
{
var k;
if (obj instanceof Object) {
for (k in obj){
if (obj.hasOwnProperty(k)){
if(k=='files')
{
scan( obj[k],1 );
}
}
}
} else {
body += 'found value : ' + obj + '<br/>';
if(append == 1)
arr.push(obj);
alert("Arr"+ arr);
};
};
scan(testJ,0);
I am not able to figure out where am I going wrong. Could some give me pointers?

var res = [];
function gather(j) {
for (var k in j) {
if (k === 'files') {
addFiles(j[k]);
} else if (typeof j[k] === 'object') {
gather(j[k]);
}
}
}
function addFiles(f) {
for (var i = 0; i < f.length; i++) {
if (typeof f[i] === "string") {
body += 'found value : ' + obj + '<br/>';
res.push(f[i]);
} else {
gather(f[i]);
}
}
}
gather(testJ);
Free tips:
instanceof is some cancerous stuff. Why does instanceof return false for some literals?
Always, always use === for comparison, not ==
I also wouldn't blindly use hasOwnProperty unless you're afraid the thing you're operating on might have a modified prototype, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in just for simplicity.

How about a map reduce approach?:
function mapJ(subject) {
return subject.files.map(function(item) {
if (typeof item === "string") {
return item;
} else {
return parseJ(item);
}
});
}
function reduceJ(subject) {
return subject.reduce(function(prev, cur) {
return prev.concat(cur);
}, []);
}
function parseJ(subject) {
return reduceJ(mapJ(subject));
}
var result = parseJ(testJ));

How can i reach a JSON node dynamically without using eval?

Path variable is unpredictable. Sometimes it is just a, sometimes a/b, sometimes a/b/c etc. I want to reach a node dynamically according to path. The code below behaves what i want but i can consider if there is a better way to do that without eval for example.
http://jsfiddle.net/nuonzngv/1/
cont = {
"a" : {
"b": {
"c": "d"
}
}
}
path = "a/b/c";
sect = path.split("/");
path = "cont";
$.each(sect, function( index, value ) {
path = path + "['" + value + "']";
});
console.log(eval(path));
Solution
I found a plugin that has a getPath function in it, for underscore.js:
https://github.com/documentcloud/underscore-contrib/blob/master/docs/underscore.object.selectors.js.md

Can you access your cont object directly in the loop? If so:
var cont = {
"a" : {
"b": {
"c": "d"
}
}
},
o = cont,
path = "a/b/c",
sect = path.split("/");
path = "cont";
$.each(sect, function(index, value) {
path = path + "['" + value + "']";
if (o) o = o[value];
});
console.log(path+'='+o);
gives:
cont['a']['b']['c']=d
An invalid path will return undefined.
*Edit: psibernetic's comment suggesting creating a standalone function:
function GetByPath(obj, path) {
var result = obj;
$.each(path.split("/"), function(index, value) {
if (typeof result !== 'undefined' && result !== null) {
result = obj[value];
}
}
return result;
}

function GetByPath(cont, path)
{
var result = cont;
$.each(path.split("/"), function(index, value) {
if(typeof result !== 'undefined' && result !== null) {
result = cont[value];
}
}
return result;
}

Is there any native function to convert json to url parameters?

I need convert json object to url form like: "parameter=12&asd=1"
I done with this:
var data = {
'action':'actualiza_resultado',
'postID': 1,
'gl': 2,
'gl2' : 3
};
var string_=JSON.stringify(data);
string_=string_.replace(/{/g, "");
string_=string_.replace(/}/g, "");
string_=string_.replace(/:/g, "=")
string_=string_.replace(/,/g, "&");
string_=string_.replace(/"/g, "");
But i wonder if there any function in javascript or in JSON object to do this?

Use the URLSearchParams interface, which is built into browsers and Node.js starting with version 10, released in 2018.
const myParams = {'foo': 'hi there', 'bar': '???'};
const u = new URLSearchParams(myParams).toString();
console.log(u);
Old answer: jQuery provides param that does exactly that. If you don't use jquery, take at look at the source.
Basically, it goes like this:
url = Object.keys(data).map(function(k) {
return encodeURIComponent(k) + '=' + encodeURIComponent(data[k])
}).join('&')

Using ES6 syntax:
var data = {
'action':'actualiza_resultado',
'postID': 1,
'gl': 2,
'gl2' : 3
};
let urlParameters = Object.entries(data).map(e => e.join('=')).join('&');
console.log(urlParameters);

I made an implementation that support nested objects and arrays i.e.
var data = {
users: [
{
"name": "jeff",
"tasks": [
"Do one thing",
"Do second thing"
]
},
{
"name": "rick",
"tasks": [
"Never gonna give you up",
"Never gonna let you down"
]
}
]
}
Will be:
users[0][name]=jeff&users[0][tasks][0]=Do%20one%20thing&users[0][tasks][1]=Do%20second%20thing&users[1][name]=rick&users[1][tasks][0]=Never%20gonna%20give%20you%20up&users[1][tasks][1]=Never%20gonna%20let%20you%20down
So, here's the implementation:
var isObj = function(a) {
if ((!!a) && (a.constructor === Object)) {
return true;
}
return false;
};
var _st = function(z, g) {
return "" + (g != "" ? "[" : "") + z + (g != "" ? "]" : "");
};
var fromObject = function(params, skipobjects, prefix) {
if (skipobjects === void 0) {
skipobjects = false;
}
if (prefix === void 0) {
prefix = "";
}
var result = "";
if (typeof(params) != "object") {
return prefix + "=" + encodeURIComponent(params) + "&";
}
for (var param in params) {
var c = "" + prefix + _st(param, prefix);
if (isObj(params[param]) && !skipobjects) {
result += fromObject(params[param], false, "" + c);
} else if (Array.isArray(params[param]) && !skipobjects) {
params[param].forEach(function(item, ind) {
result += fromObject(item, false, c + "[" + ind + "]");
});
} else {
result += c + "=" + encodeURIComponent(params[param]) + "&";
}
}
return result;
};
var data = {
users: [{
"name": "jeff",
"tasks": [
"Do one thing",
"Do second thing"
]
},
{
"name": "rick",
"tasks": [
"Never gonna give you up",
"Never gonna let you down"
]
}
]
}
document.write(fromObject(data));

You don't need to serialize this object literal.
Better approach is something like:
function getAsUriParameters(data) {
var url = '';
for (var prop in data) {
url += encodeURIComponent(prop) + '=' +
encodeURIComponent(data[prop]) + '&';
}
return url.substring(0, url.length - 1)
}
getAsUriParameters(data); //"action=actualiza_resultado&postID=1&gl=2&gl2=3"

Something I find nicely looking in ES6:
function urlfy(obj) {
return Object
.keys(obj)
.map(k => `${encodeURIComponent(k)}=${encodeURIComponent(obj[k])}`)
.join('&');
}
Later update (same thing, maybe a bit cleaner):
const urlfy = obj => Object
.keys(obj)
.map(k => encodeURIComponent(k) + '=' + encodeURIComponent(obj[k]))
.join('&');

Like #georg said, you can use JQuery.param for flat objects.
If you need to process complex objects, you can use JsonUri, a python package that does just that. There is JavaScript library for it as well
Disclaimer: I am the author of JSONURI
Edit: I learned much later that you can also just base64 encode your payload - most languages as support for base64 encoding/decoding
Example
x = {name: 'Petter', age: 47, places: ['Mozambique', 'Zimbabwe']}
stringRep = JSON.stringify(x)
encoded = window.btoa(stringRep)
Gives you eyJuYW1lIjoiUGV0dGVyIiwiYWdlIjo0NywicGxhY2VzIjpbIk1vemFtYmlxdWUiLCJaaW1iYWJ3ZSJdfQ==, which you can use as a uri parameter
decoded = window.atob(encoded)
originalX = JSON.parse(decoded)
Needless to say, it comes with its own caveats

But i wonder if there any function in javascript
Nothing prewritten in the core.
or json to do this?
JSON is a data format. It doesn't have functions at all.
This is a relatively trivial problem to solve though, at least for flat data structures.
Don't encode the objects as JSON, then:
function obj_to_query(obj) {
var parts = [];
for (var key in obj) {
if (obj.hasOwnProperty(key)) {
parts.push(encodeURIComponent(key) + '=' + encodeURIComponent(obj[key]));
}
}
return "?" + parts.join('&');
}
alert(obj_to_query({
'action': 'actualiza_resultado',
'postID': 1,
'gl': 2,
'gl2': 3
}));
There isn't a standard way to encode complex data structures (e.g. with nested objects or arrays). It wouldn't be difficult to extend this to emulate the PHP method (of having square brackets in field names) or similar though.

This one processes arrays with by changing the nameinto mutiple name[]
function getAsUriParameters (data) {
return Object.keys(data).map(function (k) {
if (_.isArray(data[k])) {
var keyE = encodeURIComponent(k + '[]');
return data[k].map(function (subData) {
return keyE + '=' + encodeURIComponent(subData);
}).join('&');
} else {
return encodeURIComponent(k) + '=' + encodeURIComponent(data[k]);
}
}).join('&');
};

Best solution for Vanilla JavaScript:
var params = Object.keys(data)
.filter(function (key) {
return data[key] ? true : false
})
.map(function (key) {
return encodeURIComponent(key) + '=' + encodeURIComponent(data[key])
})
.join('&');
PS: The filter is used here to remove null or undefined parameters. It makes the url look cleaner.

The custom code above only handles flat data. And JQuery is not available in react native. So here is a js solution that does work with multi-level objects and arrays in react native.
function formurlencoded(data) {
const opts = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
let sorted = Boolean(opts.sorted),
skipIndex = Boolean(opts.skipIndex),
ignorenull = Boolean(opts.ignorenull),
encode = function encode(value) {
return String(value).replace(/(?:[\0-\x1F"-&\+-\}\x7F-\uD7FF\uE000-\uFFFF]|[\uD800-\uDBFF][\uDC00-\uDFFF]|[\uD800-\uDBFF](?![\uDC00-\uDFFF])|(?:[^\uD800-\uDBFF]|^)[\uDC00-\uDFFF])/g, encodeURIComponent).replace(/ /g, '+').replace(/[!'()~\*]/g, function (ch) {
return '%' + ch.charCodeAt().toString(16).slice(-2).toUpperCase();
});
},
keys = function keys(obj) {
const keyarr = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : Object.keys(obj);
return sorted ? keyarr.sort() : keyarr;
},
filterjoin = function filterjoin(arr) {
return arr.filter(function (e) {
return e;
}).join('&');
},
objnest = function objnest(name, obj) {
return filterjoin(keys(obj).map(function (key) {
return nest(name + '[' + key + ']', obj[key]);
}));
},
arrnest = function arrnest(name, arr) {
return arr.length ? filterjoin(arr.map(function (elem, index) {
return skipIndex ? nest(name + '[]', elem) : nest(name + '[' + index + ']', elem);
})) : encode(name + '[]');
},
nest = function nest(name, value) {
const type = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : typeof value === 'undefined' ? 'undefined' : typeof(value);
let f = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : null;
if (value === f) f = ignorenull ? f : encode(name) + '=' + f; else if (/string|number|boolean/.test(type)) f = encode(name) + '=' + encode(value); else if (Array.isArray(value)) f = arrnest(name, value); else if (type === 'object') f = objnest(name, value);
return f;
};
return data && filterjoin(keys(data).map(function (key) {
return nest(key, data[key]);
}));
}

The conversion from a JSON string to a URL query string can be done in a single line:
const json = '{"action":"actualiza_resultado","postID":1,"gl":2,"gl2":3}';
const queryString = new URLSearchParams(JSON.parse(json)).toString();
queryString would then be set to "action=actualiza_resultado&postID=1&gl=2&gl2=3".

Based on georg's answer, but also adding ? before the string and using ES6:
const query = !params ? '': Object.keys(params).map((k, idx) => {
let prefix = '';
if (idx === 0) {
prefix = '?';
}
return prefix + encodeURIComponent(k) + '=' + encodeURIComponent(params[k]);
}).join('&');

As most of the answers only convert flat objects to query parameters, I would like to share mine.
This function can handle flat objects, as well as nested arrays/objects while only using plain JS.
function incapsulateInBrackets(key)
{
return '[' + key + ']';
}
function encode(object, isSubEncode=false, prefix = '')
{
let parts = Object.keys(object).map( (key) => {
let encodedParts = [];
if(Array.isArray(object[key]))
{
object[key].map(function(innerKey, index){
encodedParts.push( encode(object[key][index], true, prefix + key + incapsulateInBrackets(index)));
});
}
else if(object[key] instanceof Object)
{
Object.keys(object[key]).map( (innerKey) => {
if(Array.isArray(object[key][innerKey]))
{
encodedParts.push( encode(object[key][index], true, prefix + incapsulateInBrackets(key) + incapsulateInBrackets(innerKey)) );
}
else
{
encodedParts.push( prefix + incapsulateInBrackets(key) + incapsulateInBrackets(innerKey) + '=' + object[key][innerKey] );
}
});
}
else
{
if(isSubEncode)
{
encodedParts.push( prefix + incapsulateInBrackets(key) + '=' + object[key] );
}
else
{
encodedParts.push( key + '=' + object[key] );
}
}
return encodedParts.join('&');
});
return parts.join('&');
}

Make a utility if you have nodejs
const querystring = require('querystring')
export function makeQueryString(params): string {
return querystring.stringify(params)
}
import example
import { makeQueryString } from '~/utils'
example of use
makeQueryString({
...query,
page
})
Read the latest documentation here.

JavaScript function to convert JSON key-value object to query string

I'm working on formatting a URL for the Facebook Feed Dialog. There's so many parameters though. I want to have a function for these dialogs, something like:
function generateDialogUrl(dialog, params) {
base = "http://www.facebook.com/dialog/" + dialog + "?";
tail = [];
for (var p in params) {
if (params.hasOwnProperty(p)) {
tail.push(p + "=" + escape(params[p]));
}
}
return base + tail.join("&")
}
Oh wow... I think I just answered my own question. Is that right? Is escape() the correct function to use?
I'm stuck in the Lovers source code.
UPDATE: Since, we're using jQuery, I rewrote the method using jQuery.each. I also replaced escape() with encodeURIComponent() as suggested by #galambalazs & #T.J. Crowder. Thanks, guys!
var generateDialogUrl = function (dialog, params) {
base = "http://www.facebook.com/dialog/" + dialog + "?";
tail = [];
$.each(params, function(key, value) {
tail.push(key + "=" + encodeURIComponent(value));
})
return base + tail.join("&");
}
It's working!

Better yet, use encodeURIComponent instead. See this article comparing the two:
The escape() method does not encode
the + character which is interpreted
as a space on the server side as well
as generated by forms with spaces in
their fields. Due to this shortcoming
and the fact that this function fails
to handle non-ASCII characters
correctly, you should avoid use of
escape() whenever possible. The best
alternative is usually
encodeURIComponent().
escape() will not encode: #*/+

There is a jQuery method to accomplish this: $.param. It would work like this:
var generateDialogUrl = function (dialog, params) {
base = 'http://www.facebook.com/dialog/' + dialog + '?';
return base + $.param(params);
}

const createQueryParams = (param, prefix = '') => {
let queryString = '';
if (param.constructor === Object) {
queryString = Object.keys(param).reduce((result, key) => {
const obj = param[key];
const queryParam = result ? `${result}&${prefix}` : prefix;
if (obj.constructor === Object) {
return `${queryParam}${createQueryParams(obj, `${key}.`)}`;
} else if(obj.constructor === Array) {
const qp= obj.map((item, index)=> {
if (item.constructor === Object || item.constructor === Array) {
const query = createQueryParams(item, `${key}[${index}].`);
return `${query}`;
} else {
return `${key}[${index}]=${item}`;
}
}).reduce((res, cur) => {
return res ? `${res}&${cur}`: `${cur}`;
}, '');
return `${queryParam}${qp}`;
} else {
return `${queryParam}${key}=${obj}`;
}
}, '');
} else if(param.constructor === Array) {
queryString = param.reduce((res, cur) => `${res},${cur}`);
} else {
queryString = param;
}
return encodeURI(queryString);
};
Example:
createQueryParams({"Context":{"countryCode":"NO"},"Pagination":{"limit":10,"offset":1},"AdditionalField":[{"name":"Policy Number","value":"Pol123"},{"name":"Policy Version","value":"PV1"}]});

convertJsonToQueryString: function (json, prefix) {
//convertJsonToQueryString({ Name: 1, Children: [{ Age: 1 }, { Age: 2, Hoobbie: "eat" }], Info: { Age: 1, Height: 80 } })
if (!json) return null;
var str = "";
for (var key in json) {
var val = json[key];
if (isJson(val)) {
str += convertJsonToQueryString(val, ((prefix || key) + "."));
} else if (typeof (val) == "object" && ("length" in val)) {
for (var i = 0; i < val.length; i++) {
//debugger
str += convertJsonToQueryString(val[i], ((prefix || key) + "[" + i + "]."));
}
}
else {
str += "&" + ((prefix || "") + key) + "=" + val;
}
}
return str ? str.substring(1) : str;
}
isJson = function (obj) {
return typeof (obj) == "object" && Object.prototype.toString.call(obj).toLowerCase() == "[object object]" && !obj.length;
};
example:
convertJsonToQueryString({Name:1,Children:[{Age:1},{Age:2,Hoobbie:"eat"}],Info:{Age:1,Height:80}})
Result:
"Name=1Children[0].Age=1Children[1].Age=2&Children[1].Hoobbie=eatInfo.Age=1&Info.Height=80"