Javascript string to object reference (without eval() or indexes)
I've seen quite some related questions and google results, but none seem to match my problem.
I'm getting a string "header.h2" which I want to contencate to 'var objects
'.
So I want objects.header.h2
(which contains more hash data).
However, I don't want to use eval() or the often suggested buttons[]
for the obvious reason that buttons[header.h2
] won't work and I would need buttons[header][h2]
.
So how can I remain the object notation, or in the worst case, solve my p开发者_开发百科roblem?
Just a quick sketch of a possible way:
Your data:
var data = [
{foo: 1, bar: 2, foobar: [
'a', 'b', 'c'
]},
{foo: 1, bar: 2, foobar: [
'd', 'e', 'f'
]},
{foo: 1, bar: 2, foobar: [
'g', 'h', 'i'
]}
];
var accessor = '1.foobar.2';
Using a helper function:
function helper(data, accessor) {
var keys = accessor.split('.'),
result = data;
while (keys.length > 0) {
var key = keys.shift();
if (typeof result[key] !== 'undefined') {
result = result[key];
}
else {
result = null;
break;
}
}
return result;
}
Or making it available to all objects: (personally, I don't like this...)
Object.prototype.access = function (accessor) {
var keys = accessor.split('.'),
result = this;
while (keys.length > 0) {
var key = keys.shift();
if (typeof result[key] !== 'undefined') {
result = result[key];
}
else {
result = null;
break;
}
}
return result;
};
Debug output:
console.log(
helper(data, accessor), // will return 'f'
data.access(accessor) // will return 'f'
);
I would create a "populate" method which creates the object per the dot notation string it is given:
var populate = function(obj, str) {
var ss=str.split(/\./), len=ss.length, i, o=obj;
for (i=0; i<len; i++) {
if (!o[ss[i]]) { o[ss[i]] = {}; }
o = o[ss[i]];
}
return obj;
};
var objects = populate({}, 'header.h2');
objects.header.h2; // => Object {}
populate(objects, 'foo.bar.gah.zip');
objects.foo.bar.gah.zip; // => Object {}
Needs testing but should get you closer to your goal.
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