Every time I pass an array to this function, when it hits a null or undefined value it stops the loop. I can't work out how to fix this. When I ask whether the current item in the loop is null or undefined or false, it doesn't answer...
function xul(func, loc, arr){
var elem;
var props = {};
for (var i = 0, len = arr.length; i < len; i++){
if (arr[i] == undefined) {
jsdump("undefined" + " - " + len);
}
else if (arr[i] == null) {
jsdump("null" + " - " + len);
}
else if (arr[i] == false) {
jsdump("false" + " - " + len);
}
else if (typeof arr[i] == "string"){
elem = arr[i];
if (typeOf(arr[i + 1]) == "object") {
props = arr[i+1];
i++;
}
loc = createNode(func, loc, elem, props);
}
if (typeOf(arr[i + 1]) == "array") {
xul("append", loc, arr[i+1]);
} else {
return loc;
}
}
}
What is going on here?
Actually the loop stops here (if you return something you exit the loop!):
if (typeOf(arr[i + 1]) == "array") {
xul("append", loc, arr[i+1]);
} else {
return loc;
}
if the next element it's not an array it returns loc and the loop stops. check this fiddle: http://jsfiddle.net/g8SVJ/ it logs two undefined and then returns loc
You should also use === instead of ==
Related
I read an article about JSON.Parser from scratch by Tan Li Hau.
https://lihautan.com/json-parser-with-javascript/
And I want to custom his JSON.Parser which can replace "" to " or """ to ". I mean if " keep more than 1 continuously, replace to " .
ex)
'{"n": ""aaa, should, ""}'
to
'{"n": "aaa, should, "}'
But for now, there is a syntax error of course.
I found the parseString() loops while " comes next. So I tried to update parseString() to replace "" to " if it's continuously. But it's not working. Also It's not supported more than 1 ".
So if you could give me some advise, it would be helpful.
function fakeParseJSON(str) {
let i = 0;
const value = parseValue();
expectEndOfInput();
return value;
function parseObject() {
if (str[i] === "{") {
i++;
skipWhitespace();
const result = {};
let initial = true;
// if it is not '}',
// we take the path of string -> whitespace -> ':' -> value -> ...
while (i < str.length && str[i] !== "}") {
if (!initial) {
eatComma();
skipWhitespace();
}
const key = parseString();
if (key === undefined) {
expectObjectKey();
}
skipWhitespace();
eatColon();
const value = parseValue();
result[key] = value;
initial = false;
}
expectNotEndOfInput("}");
// move to the next character of '}'
i++;
return result;
}
}
function parseArray() {
if (str[i] === "[") {
i++;
skipWhitespace();
const result = [];
let initial = true;
while (i < str.length && str[i] !== "]") {
if (!initial) {
eatComma();
}
const value = parseValue();
result.push(value);
initial = false;
}
expectNotEndOfInput("]");
// move to the next character of ']'
i++;
return result;
}
}
function parseValue() {
skipWhitespace();
const value =
parseString() ??
parseNumber() ??
parseObject() ??
parseArray() ??
parseKeyword("true", true) ??
parseKeyword("false", false) ??
parseKeyword("null", null);
skipWhitespace();
return value;
}
function parseKeyword(name, value) {
if (str.slice(i, i + name.length) === name) {
i += name.length;
return value;
}
}
function skipWhitespace() {
while (
str[i] === " " ||
str[i] === "\n" ||
str[i] === "\t" ||
str[i] === "\r"
) {
i++;
}
}
function parseString() {
if (str[i] === '"') {
i++;
let result = "";
if (str[i - 1] + str[i] === '""') {
(str[i - 1] + str[i]).replace('""', '"');
}
while (i < str.length && str[i] !== '"') {
if (str[i] === "\\") {
const char = str[i + 1];
if (
char === '"' ||
char === "\\" ||
char === "/" ||
char === "b" ||
char === "f" ||
char === "n" ||
char === "r" ||
char === "t"
) {
result += char;
i++;
} else if (char === "u") {
if (
isHexadecimal(str[i + 2]) &&
isHexadecimal(str[i + 3]) &&
isHexadecimal(str[i + 4]) &&
isHexadecimal(str[i + 5])
) {
result += String.fromCharCode(
parseInt(str.slice(i + 2, i + 6), 16)
);
i += 5;
} else {
i += 2;
expectEscapeUnicode(result);
}
} else {
expectEscapeCharacter(result);
}
} else {
result += str[i];
}
i++;
}
expectNotEndOfInput('"');
i++;
return result;
}
}
function isHexadecimal(char) {
return (
(char >= "0" && char <= "9") ||
(char.toLowerCase() >= "a" && char.toLowerCase() <= "f")
);
}
function parseNumber() {
let start = i;
if (str[i] === "-") {
i++;
expectDigit(str.slice(start, i));
}
if (str[i] === "0") {
i++;
} else if (str[i] >= "1" && str[i] <= "9") {
i++;
while (str[i] >= "0" && str[i] <= "9") {
i++;
}
}
if (str[i] === ".") {
i++;
expectDigit(str.slice(start, i));
while (str[i] >= "0" && str[i] <= "9") {
i++;
}
}
if (str[i] === "e" || str[i] === "E") {
i++;
if (str[i] === "-" || str[i] === "+") {
i++;
}
expectDigit(str.slice(start, i));
while (str[i] >= "0" && str[i] <= "9") {
i++;
}
}
if (i > start) {
return Number(str.slice(start, i));
}
}
function eatComma() {
expectCharacter(",");
i++;
}
function eatColon() {
expectCharacter(":");
i++;
}
// error handling
function expectNotEndOfInput(expected) {
if (i === str.length) {
printCodeSnippet(`Expecting a \`${expected}\` here`);
throw new Error("JSON_ERROR_0001 Unexpected End of Input");
}
}
function expectEndOfInput() {
if (i < str.length) {
printCodeSnippet("Expecting to end here");
throw new Error("JSON_ERROR_0002 Expected End of Input");
}
}
function expectObjectKey() {
printCodeSnippet(`Expecting object key here
For example:
{ "foo": "bar" }
^^^^^`);
throw new Error("JSON_ERROR_0003 Expecting JSON Key");
}
function expectCharacter(expected) {
if (str[i] !== expected) {
printCodeSnippet(`Expecting a \`${expected}\` here`);
throw new Error("JSON_ERROR_0004 Unexpected token");
}
}
function expectDigit(numSoFar) {
if (!(str[i] >= "0" && str[i] <= "9")) {
printCodeSnippet(`JSON_ERROR_0005 Expecting a digit here
For example:
${numSoFar}5
${" ".repeat(numSoFar.length)}^`);
throw new Error("JSON_ERROR_0006 Expecting a digit");
}
}
function expectEscapeCharacter(strSoFar) {
printCodeSnippet(`JSON_ERROR_0007 Expecting escape character
For example:
"${strSoFar}\\n"
${" ".repeat(strSoFar.length + 1)}^^
List of escape characters are: \\", \\\\, \\/, \\b, \\f, \\n, \\r, \\t, \\u`);
throw new Error("JSON_ERROR_0008 Expecting an escape character");
}
function expectEscapeUnicode(strSoFar) {
printCodeSnippet(`Expect escape unicode
For example:
"${strSoFar}\\u0123
${" ".repeat(strSoFar.length + 1)}^^^^^^`);
throw new Error("JSON_ERROR_0009 Expecting an escape unicode");
}
function printCodeSnippet(message) {
const from = Math.max(0, i - 10);
const trimmed = from > 0;
const padding = (trimmed ? 4 : 0) + (i - from);
const snippet = [
(trimmed ? "... " : "") + str.slice(from, i + 1),
" ".repeat(padding) + "^",
" ".repeat(padding) + message
].join("\n");
console.log(snippet);
}
}
console.log(`${fakeParseJSON('{"n": ""string, should, ""}')}`);
https://codesandbox.io/embed/json-parser-with-error-handling-forked-9zetnc?fontsize=14&hidenavigation=1&theme=dark
I am using this method in order to convert an Object to QueryString. QueryString is required for ajax send request.
var objectToQueryString = function(a) {
var prefix, s, add, name, r20, output;
s = [];
r20 = /%20/g;
add = function(key, value) {
// If value is a function, invoke it and return its value
value = (typeof value == 'function') ? value() : (value == null ? "" : value);
s[s.length] = encodeURIComponent(key) + "=" + encodeURIComponent(value);
};
if (a instanceof Array) {
for (name in a) {
add(name, a[name]);
}
} else {
for (prefix in a) {
buildParams(prefix, a[prefix], add);
}
}
output = s.join("&").replace(r20, "+");
return output;
};
function buildParams(prefix, obj, add) {
var name, i, l, rbracket;
rbracket = /\[\]$/;
if (obj instanceof Array) {
for (i = 0, l = obj.length; i < l; i++) {
if (rbracket.test(prefix)) {
add(prefix, obj[i]);
} else {
buildParams(prefix + "%" + (typeof obj[i] === "object" ? i : "") + "%", obj[i], add);
}
}
} else if (typeof obj == "object") {
// Serialize object item.
for (name in obj) {
buildParams(prefix + "%" + name + "%", obj[name], add);
}
} else {
// Serialize scalar item.
add(prefix, obj);
}
}
The following code convert the object to QueryString sucessfully but the properties with no values are omitted in the return QueryString. But i want all the properties of the object. It does not matter the object properties have value or not.
If you pass a property where the value is null, then the 'obj' parameter in this call will be null:
function buildParams(prefix, obj, add) {
Can you test your results when you change your 'buildParams' function to this:
function buildParams(prefix, obj, add) {
obj = obj || "";
var name, i, l, rbracket;
rbracket = /\[\]$/;
if (obj instanceof Array) {
for (i = 0, l = obj.length; i < l; i++) {
if (rbracket.test(prefix)) {
add(prefix, obj[i]);
} else {
buildParams(prefix + "%" + (typeof obj[i] === "object" ? i : "") + "%", obj[i], add);
}
}
} else if (typeof obj == "object") {
// Serialize object item.
for (name in obj) {
buildParams(prefix + "%" + name + "%", obj[name], add);
}
} else {
// Serialize scalar item.
add(prefix, obj);
}
}
I need to check for the null values and alert them if there are any before getting saved. I have used this code but I am not able to alert the null values instead it is getting saved . .
function fn_publish() {
var SessionNames = getParameterByName('SessionName');
var MenuType = getParameterByName('MenuType');
var Date = getParameterByName('ForDate');
var publish = "Y";
Dates = Date.split("-");
Date = Dates[1] + "/" + Dates[2] + "/" + Dates[0];
var rows = [];
cols = document.getElementById('product_table').rows[1].cells.length - 1;
table = document.getElementById('product_table');
for (var i = 1; i <= cols; i++) {
for (var j = 0, row; row = table.rows[j]; j++) {
if (j == 0) {
cust = row.cells[i].innerText;
alert(cust);
} else if (j == 1) {
catlg = row.cells[i].innerText;
alert(catlg);
} else {
if (typeof (row.cells[i]) != "undefined") {
if (row.cells[i].innerText != "") {
//alert(SessionNames+"::"+MenuType+"::"+Date+"::"+catlg+"::"+row.cells[0].innerText+"::"+row.cells[i].innerText+"::"+cust+"::"+publish);
fn_insert(SessionNames, MenuType, Date, catlg, row.cells[0].innerText, row.cells[i].innerText, cust, publish);
} else {
jAlert("Please select a product", "ok");
return false;
}
}
}
}
}
jAlert("Menu Published", "ok");
}
if (row.cells[i].innerText != "") {
May be the cells are containing empty space in that. Better trim ad then compare.
if (row.cells[i].innerText.trim() !== "") {
Also instead of innerText use textContent which is common in most modern browsers.
if (row.cells[i].textContent.trim() !== "") {
I Loop through a complex JSON object but I want to stop the loop after n iterations
n = 0;
maxIterations = 100;
ObjectValues = function(v, k){
if(n == maxIterations){
if (typeof v == "object") {
for (var kp in v) {
if (Object.hasOwnProperty.call(v, kp)) {
ObjectValues(v[kp], k != undefined ? k + "." + kp : kp);
}
}
} else {
console.log(k + ":" + v);
n++;
}
}else{
console.log('I should end the function');
return false;
}
};
But I can't exit the function with return false. The function gets called, even after I tried to exit it with return false.
As I understand it, you want to recursively print maxiteration keys and their values:
n = 0;
maxIterations = 100;
ObjectValues = function(v, k){
if(n < maxIterations){
if (typeof v == "object") {
for (var kp in v) {
if (Object.hasOwnProperty.call(v, kp)) {
if(! ObjectValues(v[kp], k != undefined ? k + "." + kp : kp) )
return false;
}
}
} else {
console.log(k + ":" + v);
n++;
}
return true;
} else {
console.log('I should end the function');
return false;
}
};
I'm trying to format any kind of variables to achieve some kind of toString() method.
It's working for pretty complex objects and arrays, handling circular references, but when I try to call it on a jQuery object: format($("body")), for testing it on large complex objects, I got this error:
Unhandled exception at line 330, column 21 in ms-appx://8b94d51c-586e-4f3f-bb9c-fa75d62508cd/js/default.js
0x80004005 - Erreur d’exécution JavaScript: Erreur non spécifiée.
0x80004005 - JavaScript Run-time Error: Unspecified error. // I translated it for you
Here is my code (with a // ERROR! comment next to the line 330):
function format(arg, parents, indent) {
var maxParent = 25;
if (parents === undefined) {
parents = [];
}
if (indent === undefined) {
indent = 1;
}
if (contains(parents, arg)) {
return '<span class="brackets">[Circular]</span>';
}
if (typeof arg === 'string' && parents.length > 0) {
return '"' + htmlEntities(arg) + '"';
} else if (Array.isArray(arg)) {
parents.push(arg);
if (parents.length >= maxParent) {
return '<span class="brackets">[Array]</span>';
}
var ret = "[ ";
for (var i = 0, len = arg.length; i < len; i++) {
if (i !== 0) {
ret += ", ";
}
ret += "<br>";
ret += addIndent(indent);
ret += format(arg[i], parents, indent + 1);
}
ret += "<br>";
ret += addIndent(indent - 1);
ret += " ]";
return ret;
} else if (arg === null) {
return '<span class="void">null</span>';
} else if (arg === void 0) {
return '<span class="void">undefined</span>';
} else if (typeof arg === 'number' && (isNaN(arg) || !isFinite(arg))) {
return '<span class="void">' + arg.toString() + '</span>';
} else if (typeof arg === 'object' && arg !== null) {
if (parents.length >= maxParent) {
return '<span class="brackets">[Object]</span>';
} else {
parents.push(arg);
}
var ret = "{";
var first = true;
for (var key in arg) {
if (!first) {
ret += ", ";
}
else {
first = false;
}
ret += "<br>";
ret += addIndent(indent);
ret += key;
ret += ": ";
if (typeof arg[key] === 'function') {
ret += '<span class="brackets">[Function]</span>';
} else {
ret += format(arg[key], parents, indent + 1); // ERROR!
}
}
ret += "<br>";
ret += addIndent(indent - 1);
ret += "}";
remove(parents, arg);
return ret;
}
return arg;
}
Do you have any ideas why this error is occuring?
What can I do to fix it?
Out of the top of my head I can think that arg[key] is null by the time you call the format function. Synchronize the if statement so it executes only after arg[key] is not null.