What is the best way to create a Regex that specifically targets the initial match in every line?

Question

What is the best way to create a Regex that specifically targets the initial match in every line?

Looking for a way to efficiently copy a long list of properties without their assignments being included? Avoid retyping by using a regular expression in VSCode.

Check out this sample TypeScript code snippet:

    this.anchorBillingAddress = this.page.getByTestId('billing-address-section');
    this.anchorShippingAddress = this.page.getByTestId('shipping-address-section');
    this.anchorBilling = this.page.getByTestId('billing-section');
    this.anchorGeneral = this.page.getByTestId('general-section');
    this.anchorStatistics = this.page.getByTestId('statistics-section');

The desired output:

this.anchorBillingAddress

this.anchorShippingAddress

this.anchorBilling

this.anchorGeneral

this.anchorStatistics

Attempted solution using this[^\s]+ resulted in copying the assignments as well. How can I modify the regex to stop at the first white space on each line?

javascript regex

Answer 1

Answer №1

If you're looking to identify instances of this. in your code, you can utilize the following regular expressions:

\b(this\.[A-Za-z0-9_]+)(?=\s*=)
\b(this\.\w+)(?=\s*=) or
```
^\s*\b(this\.[A-Za-z0-9_]+)(?=\s*=)
```

Using these patterns will help you locate the first occurrence of this..

const p = /\b(this\.\w+)(?=\s*=)/gm;
const s = `    this.anchorBillingAddress = this.page.getByTestId(

'billing-address-section'

);
    this.anchorShippingAddress = this.page.getByTestId(

'shipping-address-section'

)

;
    this.anchorBilling = this.page.getByTestId('billing-section');
    this.anchorGeneral = this.page.getByTestId('general-section');
    this.anchorStatistics = this.page.getByTestId('statistics-section');`;

const matches = s.match(p);
if (matches) {
  matches.forEach((match, index) => {
    console.log(`${index}=> ${match}`);
  });
}

Please Note:

\s*: Indicates zero or more spaces.
\b: Represents a word boundary.
(this\.[A-Za-z0-9_]+)(?=\s*=): Captures text from this. up to the first \s or =. The expression [A-Za-z0-9_] is equivalent to \w.
(?=\s*=): Utilizes positive lookahead to match the pattern \s*= immediately after this\.[A-Za-z0-9_]+.

Answer 2

If you're looking to identify instances of this. in your code, you can utilize the following regular expressions:

\b(this\.[A-Za-z0-9_]+)(?=\s*=)
\b(this\.\w+)(?=\s*=) or
```
^\s*\b(this\.[A-Za-z0-9_]+)(?=\s*=)
```

Using these patterns will help you locate the first occurrence of this..

const p = /\b(this\.\w+)(?=\s*=)/gm;
const s = `    this.anchorBillingAddress = this.page.getByTestId(

'billing-address-section'

);
    this.anchorShippingAddress = this.page.getByTestId(

'shipping-address-section'

)

;
    this.anchorBilling = this.page.getByTestId('billing-section');
    this.anchorGeneral = this.page.getByTestId('general-section');
    this.anchorStatistics = this.page.getByTestId('statistics-section');`;

const matches = s.match(p);
if (matches) {
  matches.forEach((match, index) => {
    console.log(`${index}=> ${match}`);
  });
}

Please Note:

\s*: Indicates zero or more spaces.
\b: Represents a word boundary.
(this\.[A-Za-z0-9_]+)(?=\s*=): Captures text from this. up to the first \s or =. The expression [A-Za-z0-9_] is equivalent to \w.
(?=\s*=): Utilizes positive lookahead to match the pattern \s*= immediately after this\.[A-Za-z0-9_]+.

Answer 3

Answer №2

To halt at the initial space, you can use this method

^this[^\s]+

The ^ ensures it commences from the beginning and disregards the subsequent this.

Answer 4

To halt at the initial space, you can use this method

^this[^\s]+

The ^ ensures it commences from the beginning and disregards the subsequent this.

Answer 5

Answer №3

If you want to extract all left hand side assignment parts that start with "this.", you can use the regular expression /this\.\S+(?=\s*=)/g

For example, applying this regex to the given text will capture assignments like "this.currentDate", "this.anchorBillingAddress", and others.

const text=`let a = this.currentDate;
this.anchorBillingAddress = this.page.getByTestId('billing-address-section');
// a comment
this.anchorShippingAddress = this.page.getByTestId('shipping-address-section');
let b = this.should.not.be.captured;
console.log(this.property);
this.anchorBilling = this.page.getByTestId('billing-section');
this.anchorGeneral = this.page.getByTestId('general-section');
this.anchorStatistics = this.page.getByTestId('statistics-section');`;

console.log(text.match(/this\.\S+(?=\s*=)/g));

The positive lookahead in the regex pattern, (?=\s*=), ensures that the extracted text is immediately followed by whitespace and an equal sign ("=").

Answer 6

If you want to extract all left hand side assignment parts that start with "this.", you can use the regular expression /this\.\S+(?=\s*=)/g

For example, applying this regex to the given text will capture assignments like "this.currentDate", "this.anchorBillingAddress", and others.

const text=`let a = this.currentDate;
this.anchorBillingAddress = this.page.getByTestId('billing-address-section');
// a comment
this.anchorShippingAddress = this.page.getByTestId('shipping-address-section');
let b = this.should.not.be.captured;
console.log(this.property);
this.anchorBilling = this.page.getByTestId('billing-section');
this.anchorGeneral = this.page.getByTestId('general-section');
this.anchorStatistics = this.page.getByTestId('statistics-section');`;

console.log(text.match(/this\.\S+(?=\s*=)/g));

The positive lookahead in the regex pattern, (?=\s*=), ensures that the extracted text is immediately followed by whitespace and an equal sign ("=").

Answer 7

Answer №4

To transfer the lines to their desired location in VS Code, follow these steps:

Begin by pressing Ctrl+H to bring up the find/replace dialog
If regex support is not already enabled, activate it by pressing Alt+R
In the find field, enter ^\s*(this\.\w+).*
Input $1 in the replace field:

https://i.sstatic.net/iV3RpGWj.png
Complete the replacements by hitting Ctrl+Alt+Enter.

Answer 8

To transfer the lines to their desired location in VS Code, follow these steps:

Begin by pressing Ctrl+H to bring up the find/replace dialog
If regex support is not already enabled, activate it by pressing Alt+R
In the find field, enter ^\s*(this\.\w+).*
Input $1 in the replace field:

https://i.sstatic.net/iV3RpGWj.png
Complete the replacements by hitting Ctrl+Alt+Enter.

What is the best way to create a Regex that specifically targets the initial match in every line?

Answer №1

Please Note:

Answer №2

Answer №3

Answer №4

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