Parse WHERE clause in node.js

Question

I'm trying to parse WHERE clause of mysql query into an expression to get data from json file

For example:

`price`=8.95 AND `title`="The Lord price= AND of the Rings"

above example should be converted to the below string after replacing price and title value on left hand side

8.95==8.95 && 'The Lord price= AND of the Rings'=="The Lord price= AND of the Rings"

I have created one code (jsfiddle) to achieve this but this will break if I add AND ` in value as show below (it returns false if condition is not matching)

var obj = {price: 8.95, title: "'The Lord price= AND `of the Rings'"};
var whereString = '`price`=8.95 AND `title`="The Lord price= AND `of the Rings"';

So I wanted to understand is there any other better way to achieve this?

Ωmega · Accepted Answer · 2020-04-05 14:51:07Z

1

In first step split your whereString with regex pattern

/(`[^`]+`=(?:"[^"]+"|\S+))(?:\s+AND\s+|$)/g

and store all Group 1 matches.

In second step do substitutions for each match and finally merge all matches with string AND

answered Apr 5, 2020 at 14:51

Ωmega

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oriberu · Accepted Answer · 2020-04-05 16:07:49Z

1

Slightly different approach, indifferent to the form the quoted string takes; split by AND outside of quotes, replace and join:

let source = '`price`=8.95 AND `title`="The Lord price= AND of the Rings"';
let result = source
    .split(/\s*\bAND\b\s*(?![^`"]+")/)
    .map(s => s.replace(/`\w+`=(.*)/, '$1==$1'))
    .join(' && ');

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

edited Apr 5, 2020 at 16:07

answered Apr 5, 2020 at 15:50

oriberu

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