Question

I am problem with using === to compare string
I get whole data from text file and split value line by line with (‘\n’)
like readLine() in java
and want to find string “SECTION” but can’t find.

when i put

if(contents[i] === "SECTION") {
    alert("This is section");
}

no alert! I am sure text file have word “SECTION”

but

if (contents[i].match("SECTION)) 

is work.

any suggestion ? thanks

---

javascript

function readFile (evt) {
var files = evt.target.files;
    if (files) {
        for (var i=0, f; f=files[i]; i++) {
            var file = files[i];           
            var reader = new FileReader();
            reader.onload = function() { 
                var contents = [];
                contents = this.result.split("\n");
                    for (var i = 0; i < contents.length; i++) {
                        if(contents[i] === "SECTION") {
                            alert("This is section");
                        }
                        document.getElementById('textArea').innerHTML +=contents[i];
                    }
            }
            reader.readAsText(file);
        }
    }
}

Answer 1

There is a bit of weirdness in your code, but:

var contents = [];
contents = this.result.split("\n");

There is no need for both lines, the second assignment overwrites the first, so:

var contents = this.result.split("\n");

.

for (var i = 0; i < contents.length; i++) {
    if(contents[i] === "SECTION") {

There is no need for === here, though I guess it doesn’t hurt. It may be that there is whitespace around the comparison text, so you might consider either removing whitespace or using a regular expression instead, e.g.:

var re = /^\s*SECTION\s*$/;

to match the word “SECTION” with optionally any amount of whitespace before and after. If you just want a line that contains the character sequence SECTION, then:

var re = /\s*SECTION\s*/;

and ignoring case:

var re = /\s*SECTION\s*/i;

whatever. Then use the test method like:

for  ( ... ) {
    if (re.test(contents[i])) {
       /* found a section */