Converting legacy functions to ECMAScript

ECMAScript follows its own string parsing rules. Hence, while converting legacy functions to ECMAScript, ensure that you adhere to the following guidelines:

All strings must be enclosed in quotation marks, with appropriate escape sequences:
- Quotation marks within the value of the string must be preceded by a backslash (\")
- Backslashes must be preceded by another backslash (\\)
  Example legacy function:
```
setTag(testFileName, C:\myfile.txt)
```
  After conversion to ECMAScript:
```
setTag("testFileName", "C:\\myfile.txt")
```
  or
```
testFileName = "C:\\myfile.txt"
```
Replace the null() function with the null keyword.
Example legacy function:
```
setTag(testTag, null())
```
After conversion to ECMAScript:
```
setTag("testTag", null)
```
or
```
testTag = null
```
Although the setTag() function is still valid in ECMAScript, you can assign values directly instead:
Example legacy function:
```
setTag(testTag, newValue)
```
After conversion to ECMAScript:
```
testTag = "newValue"
```
or
```
tags["testTag"] = "newValue"
```
Note: A direct reference to a tag named id must be qualified with tags. In ECMAScript you can reference a tag with:
```
tags["myTagName"]
tags.get("myTagName")
tags.myTagName
myTagName
```
When the tag name is id, tags.id resolves correctly during execution.
Similarly, you can replace the legacy add() function with an operator:
Example legacy function:
```
add(%%testTag%%, 1)
```
After conversion to ECMAScript:
```
testTag + 1
```
ECMAScript functions do not recognize double percent signs (%%). Therefore, when you write a function, do not enclose the tags in double percent signs as you would in a legacy function. HCL OneTest™ API tags are automatically exposed as ECMAScript local variables.
- In most cases, you can treat the tag name as a local variable:
  Example legacy function:
```
resetTags(%%variable%%)
```
  After conversion to ECMAScript:
```
resetTags(variable)
```
  Example legacy function:
```
xpath(%%xml%%, %%xpathString%%)
```
  After conversion to ECMAScript:
```
xpath(xml, xpathString)
```
- Tag names that include symbols or reserved words can cause problems; in those cases use the tags["tagname"] style of notation.
  Same example, after conversion to ECMAScript:
```
xpath(tags["xml"], tags["xpathString"])
```

For more information, see this technote about using tags with ECMAScript.